Strengthen the reference for the Handler responder. In some occasions, the handler was garbage-collected between the time the request was submitted and until it returned.
Gradle fixes
Merge branch 'master' of github.com:loopj/android-async-http
Gradle version update
Merge pull request #425 from orientalsensation/AsyncHttpResponseHandler

Strengthen the reference for the Handler responder.
Updated Gradle configuration
Updated code validity, manually merged #472
Manually merged, Closing #471
Manually merged, Closing #469
Manually merged, Closing #468
Updated Travis build configuration
Added warning, when headers overwrite each other, Closes #488
Fixed README, Closing #461
Merged manually, Closing #470
Merged manually, Closing #476
Possibility to add int and long request params, #423
Added RangeFileAsyncHttpResponseHandler, #423
Correct validation of returned String where JSON is expected
RangeFileAsyncHttpResponseHandler dependency updated, #423
Added cancelAllRequests method, #423