Merge pull request #1679 from msqr/development

Update project to build for arm64 on iOS targets, re #1677.
Fix documentation error. closes #1684
Introduce RKStatusCodesOfResponsesWithOptionalBodies

Closes #1685
Fix Travis `pod install` error
Use @rpath as the `INSTALL_PATH` for the Static Library and Framework targets. closes #1682

For more details, see: http://www.dribin.org/dave/blog/archives/2009/11/15/rpath/ and https://developer.apple.com/library/mac/documentation/developertools/conceptual/DynamicLibraries/100-Articles/RunpathDependentLibraries.html
Add unit test for github issue #1695
Fix issue with deletion of managed objects if a response mapper error is encountered. closes #1695
Remove extra whitespace
Merge pull request #1700 from novkostya/bugfix/1695

Prevents deletion of managed objects if a response mapper error is encountered
Merge pull request #1691 from RestKit/testing/travis_fix

Fix Travis `pod install` error
Update AFNetworking to 1.3.3. Fixes #1696
Merge pull request #1701 from saniul/development

Update AFNetworking to 1.3.3. Fixes #1696
Check for presence of cached and response ETags. Fixes #1599
Merge pull request #1708 from RestKit/bugfix/nil-etag

Check for presence of cached and response ETags. Fixes #1599
Merge pull request #1686 from RestKit/bugfix/no-content-type

Introduce RKStatusCodesOfResponsesWithOptionalBodies