2.3.1

Bump podspec to 2.3.1
Add danger
Add tests again
Update README with caramba info
Updated podspec info
Bump Realm version
Fix esamples
Fix a few things in the README
Merge pull request #272 from carambalabs/remove-rx-carthage
Remove Reactive framework and Carthage
Create tests target
Update pods
Remove Carthage project and Reactive references in the README file
Remove Carthage, Rx and ReactiveCocoa
Create .pullapprove.yml
Update README
Add files via upload
Update Cartifle.resolved
Merge pull request #270 from dukemike/issues/269
only perform version checks on debug builds. refs #269
only perform version checks on debug builds. refs #269