Add assertions to `RKMIMETypeSerialization` and `RKTestFixture`
Rework deletion operations to avoid deleting objects that would be valid if mapping we allowed to assign them to the desintation relationship. refs #1225
Add currentOffset to RKPaginator
Make deletion of newly inserted objects that fail validation configurable. closes #1281
Added test case for NSMutableSet mapping on managed object. refs #1201
Fix test breakage under Mac OS X
Added test cases attempting to reproduce duplicated objects issue. refs #1228
Fix small typo in README
Fix incorrect serialization of a single object inputted as an array. closes #1289
Bump version to 0.20.0
Update Podspec to v0.20.0
Merge branch 'release/0.20.0' into development
Fix issues with 304 caching when there are no Fetch Request Blocks registered that match the URL. closes #1294
Bump AFNetworking Podspec dependency and submodule reference to 1.2.0
Cleanup inadventantly raised logging during tests
Drop pre from README.md install instructions
Add another shared object factory method flavor.
Revert "Add another shared object factory method flavor."

This reverts commit 6c842b4fdbd185643280a936b31a950c3032b6ed.
Fix some erroneous comments in the documentation
Fix link breakage due to relative link changes in Github Markdown