Added additional development tools

Author: craigem

shell.nix

@@ -1,10 +1,13 @@
 with (import ./overlay) {};
 
-# A basic shell with some tools available.
+# A basic shell with some tools available for porting devices.
 mkShell rec {
   name = "nixos-mobile";
   buildInputs = [
-    mkbootimg
-    dtbTool
+    dtbTool                   # Combines multiple device tree blobs into one image
+    file                      # Shows the type of files
+    lz4                       # Decompress image files
+    mkbootimg                 # Pack and unpack boot images
+    python3Packages.binwalk   # Search a binary image for embedded files
   ];
 }