Fix equivalence tests for request and response descriptors.
Simplify testing for pathPattern and keyPath equality per segiddins' suggestion.
Fix equivalence test for property mappings which may also have nil string attributes in the case of relationship mappings.
dynamic mapping equivalence just checks pointer identity
Merge pull request #1940 from peebsjs/make-dynamic-mapping-equality-pointer-identity

Dynamic mapping equivalence should just check pointer identity
[README] Switch to shields.io for README badges
Merge pull request #1941 from RestKit/shields-badges

[README] Switch to shields.io for README badges
[README] Link up badges
[SOCKit] Switch Vendored SOCKit to submodule, v1.1

Closes https://github.com/RestKit/RestKit/issues/1939
Fix -[RKPropertyMapping isEqualToMapping:] when sourceKeyPath is nil

Closes https://github.com/RestKit/RestKit/issues/1936
Fix -[RKObjectMapping mappingForSourceKeyPath:] when sourceKeyPath is nil

Closes https://github.com/RestKit/RestKit/issues/1937
Update CI rake task
Switch test automation to xctasks
Update to RakeUp 1.2.0
Drop debugger from server
Switch to Expecta HEAD to fix issue with Objective-C++ files
Drop Brewfile
[Travis] Remove `brew bundle` from travis
Fix typo in lint task execution
Make RKCoreData.h public for frameworks