Fixup project, update README and guides

Summary:
- Fix OCMock issues with tvOS tests
- Update README/guides
Closes #737

Differential Revision: D5052333

Pulled By: jessesquires

fbshipit-source-id: 958444d892c14dd4c75e244f20ae21bbfeec8290

Author: jessesquires

Guides/Installation.md

@@ -9,7 +9,7 @@ The preferred method of installation for `IGListKit` is using [CocoaPods](https:
 In order to use the latest release of the framework, add the following to your `Podfile`:
 
 ```ruby
-pod 'IGListKit', '~> 3.0.0'
+pod 'IGListKit', '~> 3.0'
 ```
 
 ### Using `master`
@@ -29,7 +29,7 @@ With the exception of `macOS` (which currently only supports the diffing algorit
 However, if you only want to use the diffing components of this library, then you can use the diffing subspec in your `Podfile`:
 
 ```ruby
-pod 'IGListKit/Diffing', '~> 3.0.0'
+pod 'IGListKit/Diffing', '~> 3.0'
 ```
 
 Regardless of whether you only use the diffing components, or the entire library, the imports are the same:
@@ -43,5 +43,5 @@ import IGListKit
 If using [Carthage](https://github.com/Carthage/Carthage), add the following to your `Cartfile`:
 
 ```ogdl
-github "Instagram/IGListKit" ~> 3.0.0
+github "Instagram/IGListKit" ~> 3.0
 ```

Podfile

@@ -1,6 +1,5 @@
 source 'https://github.com/CocoaPods/Specs.git'
 use_frameworks!
-platform :ios, '8.0'
 
 workspace 'IGListKit'
 

Podfile.lock

@@ -7,6 +7,6 @@ DEPENDENCIES:
 SPEC CHECKSUMS:
   OCMock: 35ae71d6a8fcc1b59434d561d1520b9dd4f15765
 
-PODFILE CHECKSUM: c1d61b6e03649cc2671f4ec29d6e8fb07238b6de
+PODFILE CHECKSUM: b27692418c91f87e51125b014298a4f9372c5441
 
 COCOAPODS: 1.2.1