Merge pull request #20 from mceyberg/master

Added missing active_support/notifications require statement. Added .idea to .gitignore.
Add multipart response support.
Don't manually set content-type
Don't convert data to json manually; allow middleware to handle it.
Merge pull request #22 from ncolgan/multipart_support

Add multipart response support.
Merge pull request #4 from code42/master

Merge base updates into fork