#1010506 by dww, chx, hgurol: Fixed FileTransfer doesn't properly handle any advanced settings nor the ssh username

#609772 by dww, JacobSingh, ksenzee: Fixed Impossible to extend the FileTransfer class system in contrib

#602520 by JacobSingh and dww: Make FileTransfer form have one option for FTP (ftp_extension() preferred).

- Patch #395472 by JacobSingh, chx, cwgordon7: more improvements to the file transfer system to pave the path for a plugin manager.  Heroic effort.

- Patch #395472 by chx, dww, cwgordon7, JacobSingh, et al: added different file transport mechanisms to core in preparation of a plugin manager.