updated RKResponseDescriptor and migrated tests to SenTestCases
fixed issue with git submodule not pointing to public URL
fixed ternary statements and project file
changed cibuild to use bundle
Revert "changed cibuild to use bundle"

This reverts commit 414977f77a9d43a83e56d04a3504d395fbba422e.
Drop skeleton parameter constraints test
Drop MIMEKit in favor of relying on AFN for all content serialization
Drop Specta
Bump Rake dependency to 10.1.1
Rework serialization integration with AFNetworking to delegate all content responsibilities upstream
Merge remote-tracking branch 'origin/experimental/rkresponse-descriptor' into experimental/port-to-afnetworking-2.0
Fix serialization breakage