fixed zero-length appendData bug and added appendPartWithStreamingURL method
close input buffer when creating multpart form from streaming nsurl
merge before the storm
reimplemented multipart form data to use a body streaming object that aggregates file streams and in-memory data objects to compose the request body just in time. also trimmed the multipart form body public API and added CoreMobileServices framework to enable lookup of MIME type by file extension.
moved mobilecoreservices framework in xcode proj
rejigger things to do callbacks and end-of-stream read properly
Merge remote-tracking branch 'upstream/master' into experimental-extreme-streaming
merged multipart streaming thingy
Adding back -appendPartWithFileData:...
Re-indenting and fixing method signature spacing
Stashing progress
Design is coming together, but something is off about the exact implementation
Fix parsing of HTTP Accept headers
Merge branch 'master' of https://github.com/peymano/AFNetworking into peymano-master
Minor refactoring and reformatting
Moving AFSwizzleClassMethodWithClassAndSelectorUsingBlock function
Minor restructuring of project file and app delegate in example
This is a working version of multipart streaming.

 - Fixed missing CRLF after header string.
 - Fixed not traversing through the buffer while reading.
 - Fixed content length of body stream are incorrect when attempts to finalize the multipart form data due to boundary settings not set yet.
 - Create a method named `setInitialAndFinalBoundaries` that attempts to reset all HTTP body parts boundary settings first before setting the initial and final boundaries.

Tested successfully on my own codes that does photo uploading to Flickr using `appendPartWithFileData:name:fileName:mimeType:`. I have not tried uploading from file URL but don't foresee any issue.
Preventing negative values for the activity indicator counter
Use MAX to constrain _activityCount to non-negative numbers