moving DFU and SSP out of GCS uploader plugin into ./libs
moving HID out ophid into ./libs
renaming ophid plugin to usbconnection (to match serialconnection and ipconnection plugins)
have uploadertool use DFU from ./libs
Note that, since LP-458, uploadertool and GCS uploader use identical versions of SSP and (almost) identical versions of DFU.
Expected benefits are:
uploadertool to work over hid/usb (not possible currently)
GCS uploader support of OpenPilot GPS flashing
That last item is tricky from a UI point of view as the GCS uploader does not work well for GPS style of board.
GPS has the OpenPilot bootloader (allowing DFU mode) but does not support UAVTalk.
This means that some UAVTalk specifics (IAP triggered reboot, ...) need to be disabled for GPS. It is not clear how to change the UI to handle GPS...