Added additional default binary response handled content types #573
Handling correctly null URLs in calls, related to #572
Fixed #537
Provided way to clear all headers Closing #581
Javadoc issue fixed [skip ci]
Added contribution rules [ci skip]
Wrong file name [ci skip]
MD Formatting of CONTRIBUTING.md
Added SAX AsyncHttpResponseHandler implementation
Added SAX integration Sample
Javadoc updated
Merge remote-tracking branch 'origin/master'
Fixed many unchecked call warnings during compile time
Added License declaration to Library where applicable
Added License declaration to Sample application where applicable
Added package-info.java files
Removed obsolete examples
Formatted whole codebase
Merge remote-tracking branch 'upstream/master'

Conflicts:
	library/src/main/java/com/loopj/android/http/SaxAsyncHttpResponseHandler.java