Merge pull request #89 from nitsch/fix-warnings

Fixed warnings
Update address of mailing list
Moved retrieval of Move's serial to happen prior to switching to DFU mode. It won't retrieve anything otherwise since the Move will not act as HID anymore in this mode.
Added optional switch --btdfu to the psmove_dfu_mode utility. This allows switching to BTDFU mode, not only STDFU mode as before.