Upgraded solidity version

lib/Addresses.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.0;
+pragma solidity >=0.4.25 <0.6.0;
 
 /**
  * Addresses Library
@@ -17,7 +17,7 @@ library Addresses {
      * @param _base The address on the network to check if it is a contract
      * @return bool Returns true if it is a valid contract
      */
-    function isContract(address _base) returns (bool _r) {
+    function isContract(address _base) public returns (bool _r) {
         assembly {
             _r := gt(extcodesize(_base), 0)
         }

lib/Integers.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.0;
+pragma solidity >=0.4.25 <0.6.0;
 
 /**
  * Integers Library
@@ -18,14 +18,14 @@ library Integers {
      * @param _value The ASCII string to be converted to an unsigned integer
      * @return uint The unsigned value of the ASCII string
      */
-    function parseInt(string _value) 
+    function parseInt(string memory _value)
         public
         returns (uint _ret) {
         bytes memory _bytesValue = bytes(_value);
         uint j = 1;
         for(uint i = _bytesValue.length-1; i >= 0 && i < _bytesValue.length; i--) {
-            assert(_bytesValue[i] >= 48 && _bytesValue[i] <= 57);
-            _ret += (uint(_bytesValue[i]) - 48)*j;
+            assert(uint8(_bytesValue[i]) >= 48 && uint8(_bytesValue[i]) <= 57);
+            _ret += (uint(uint8(_bytesValue[i])) - 48)*j;
             j*=10;
         }
     }
@@ -40,11 +40,11 @@ library Integers {
      */
     function toString(uint _base) 
         internal
-        returns (string) {
+        returns (string memory) {
         bytes memory _tmp = new bytes(32);
         uint i;
         for(i = 0;_base > 0;i++) {
-            _tmp[i] = byte((_base % 10) + 48);
+            _tmp[i] = byte(uint8((_base % 10) + 48));
             _base /= 10;
         }
         bytes memory _real = new bytes(i--);
@@ -82,7 +82,7 @@ library Integers {
      */
     function toBytes(uint _base) 
         internal
-        returns (bytes _ret) {
+        returns (bytes memory _ret) {
         assembly {
             let m_alloc := add(msize(),0x1)
             _ret := mload(m_alloc)

lib/Strings.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.0;
+pragma solidity >=0.4.25 <0.6.0;
 
 /**
  * Strings Library
@@ -24,10 +24,10 @@ library Strings {
      * @param _value The value to be the concatenated suffix
      * @return string The resulting string from combinging the base and value
      */
-    function concat(string _base, string _value)
+    function concat(string memory _base, string memory _value)
         internal
         pure
-        returns (string) {
+        returns (string memory) {
         bytes memory _baseBytes = bytes(_base);
         bytes memory _valueBytes = bytes(_value);
 
@@ -64,7 +64,7 @@ library Strings {
      * @return int The position of the needle starting from 0 and returning -1
      *             in the case of no matches found
      */
-    function indexOf(string _base, string _value)
+    function indexOf(string memory _base, string memory _value)
         internal
         pure
         returns (int) {
@@ -87,7 +87,7 @@ library Strings {
      * @return int The position of the needle starting from 0 and returning -1
      *             in the case of no matches found
      */
-    function _indexOf(string _base, string _value, uint _offset)
+    function _indexOf(string memory _base, string memory _value, uint _offset)
         internal
         pure
         returns (int) {
@@ -114,7 +114,7 @@ library Strings {
      *              otherwise this is the string to be measured
      * @return uint The length of the passed string
      */
-    function length(string _base)
+    function length(string memory _base)
         internal
         pure
         returns (uint) {
@@ -133,10 +133,10 @@ library Strings {
      * @param _length The length of the sub string to be extracted from the base
      * @return string The extracted sub string
      */
-    function substring(string _base, int _length)
+    function substring(string memory _base, int _length)
         internal
         pure
-        returns (string) {
+        returns (string memory) {
         return _substring(_base, _length, 0);
     }
 
@@ -153,10 +153,10 @@ library Strings {
      * @param _offset The starting point to extract the sub string from
      * @return string The extracted sub string
      */
-    function _substring(string _base, int _length, int _offset)
+    function _substring(string memory _base, int _length, int _offset)
         internal
         pure
-        returns (string) {
+        returns (string memory) {
         bytes memory _baseBytes = bytes(_base);
 
         assert(uint(_offset+_length) <= _baseBytes.length);
@@ -186,9 +186,14 @@ library Strings {
      * @return string[] An array of values split based off the delimiter, but
      *                  do not container the delimiter.
      */
-    function split(string _base, string _value)
+    function split(string memory _base, string memory _value, string[] storage splitArr)
         internal
-        returns (string[] storage splitArr) {
+        returns (string[] storage) {
+
+        while (splitArr.length > 0) {
+            splitArr.pop();
+        }
+
         bytes memory _baseBytes = bytes(_base);
         uint _offset = 0;
 
@@ -223,7 +228,7 @@ library Strings {
      * @param _value The string the base is being compared to
      * @return bool Simply notates if the two string have an equivalent
      */
-    function compareTo(string _base, string _value) 
+    function compareTo(string memory _base, string memory _value)
         internal
         pure
         returns (bool) {
@@ -256,7 +261,7 @@ library Strings {
      * @return bool Simply notates if the two string have an equivalent value
      *              discarding case
      */
-    function compareToIgnoreCase(string _base, string _value)
+    function compareToIgnoreCase(string memory _base, string memory _value)
         internal
         pure
         returns (bool) {
@@ -287,10 +292,10 @@ library Strings {
      *              otherwise this is the string base to convert to upper case
      * @return string 
      */
-    function upper(string _base) 
+    function upper(string memory _base)
         internal
         pure
-        returns (string) {
+        returns (string memory) {
         bytes memory _baseBytes = bytes(_base);
         for (uint i = 0; i < _baseBytes.length; i++) {
             _baseBytes[i] = _upper(_baseBytes[i]);
@@ -308,10 +313,10 @@ library Strings {
      *              otherwise this is the string base to convert to lower case
      * @return string 
      */
-    function lower(string _base) 
+    function lower(string memory _base)
         internal
         pure
-        returns (string) {
+        returns (string memory) {
         bytes memory _baseBytes = bytes(_base);
         for (uint i = 0; i < _baseBytes.length; i++) {
             _baseBytes[i] = _lower(_baseBytes[i]);