refactor(client/js/ajax.requester.js): #898 - Allow caller to specify body for request

The ajax requester base module is getting a bit hairy.  I will need to spend some time rethinking the API
and the logic used to determine the parameters and the body of the request.
feat(client/js/s3/multipart.abort.ajax.requester.js): #898 - Stub for S3 abort REST calls

These types of requests will need to be sent when an in-progress upload is cancelled.
feat(client/js/s3/multipart.complete.ajax.requester.js): #898 - S3 Complete Multipart REST call transport

These types of requests will need to be sent after we send the last part of a file.  This instructs
AWS to combine all of the parts and response when the file has been created.
refactor(form & xhr handlers): #898 - renames & spacing issues
feat(client/js/s3/handler.xhr.js): #898 - start of support for chunking
feat(client/js/s3/signature.ajax.requester.js): #898 - rename file & constructor
feat(client/js/s3/multipart.initiate.ajax.requester.js): #898 - comments and minor adjustments
feat(Gruntfile.coffee): #898 - reference multipart requesters, rename initiate requester