Update to Xcode 7 and CP 0.39

[dbgrandi]

Lots of little things to get this back in shape.

• update podspec to 0.39.0
• updated models with rake task
• updated test target to XCTest
• deleted a few duplicate methods from rake task
• ran pod update on Demo project
• commented out ReactiveCocoa in Demo project AppDelegate
• added a new AFNetworking3 json fixture (unused for now)
• got tests :green_heart: again

Meanwhile, here in NYC...

[dbgrandi]

Can definitely consider this a WIP because I need to update the non-generated model files to include some of the new features that have been added to modern CP. (e.g. plugins, social_media_url, etc.)

[dbgrandi]

Getting closer...tests pass, but podspec doesn't lint.

[dbgrandi]

Some questionable decisions in those last two commits. I had an issue that I did not fully grok, but managed to get things back to green.

- ERROR | [OSX] xcodebuild:  YAML-Framework/YAMLSerialization.h:11:9: error: include of non-modular header inside framework module 'YAML_Framework.YAMLSerialization' [-Werror,-Wnon-modular-include-in-framework-module]

Quick Solution:

• added --allow-warnings to pod lint
• added s.compiler_flags = '-Wno-non-modular-include-in-framework-module' to .podspec

[orta]

Alright, so I feel like this is good enough with a YAGNI sense for what we need for CP.app, this project has been dormant for 2 years so any improvement is :+1: - lets see what else we need as CP.app grows.