Merge branch 'refactored_sdk' into 'master'

Refactored Sdk
added TODO in ApiResponse  (for enum)
UploadManager - removed import.
UploadManager - variable name change.
UploadManagerWorker - added IllegalArgumentExceptions and fixed thread not being started by executor.
UploadManagerWorker - added IllegalArgumentExceptions and fixed thread not being started by executor.
UploadProcess checks for credentials before uploading. Poll/Resumable check credentials each iteration.
MFDefaultExecutor and MFPausableExecutorService removed (unused).
MFHttpRunner renamed to MFDefaultHttpProcessor and MFHttpProcessor interface added (for later refactor)
MFTokenFarm - changes related to MFHttpRunner renamed to MFDefaultHttpProcessor and MFHttpProcessor interface added (for later refactor)
MFApi - corrected USER_REGISTER enum constructor.
UploadManager no longer subclasses from UploadManagerWorker. Changes reflected in UploadProcess subclasses.
simplified uploader.
moved packages.
applied builder pattern to upload options
added new Constructor for MFUploadItemOptions.
renamed MFUpload to MFUploadRunnable.
check for whether MFTokenFarm is started before borrowing tokens or IllegalStateException is thrown.
check for whether MFTokenFarm is started before borrowing tokens or IllegalStateException is thrown.
fixexd check upload issue (used hashmap instead of linkedhashmap so order was off)