Fix compilation warnings (LLVM 6.0)
Merge branch 'master' of ssh://repos.visualitysoftware.com:7999/baa/baasbox-cocoa-sdk
Global async dispatch for post, put, get and delete calls
Check for null error message
Merge commit '3782a1bf24b4a55745b0bdf0d306320aa2ddd5a8'

Conflicts:
	BaasBox-iOS-SDK/BAAClient.h
	BaasBox-iOS-SDK/BAAObject.h
	BaasBoxSDK.podspec
Merge branch 'master' of github.com:VisualitySoftware/BaasBox-iOS-SDK
Merge branch 'master' of https://github.com/VisualitySoftware/BaasBox-iOS-SDK