Instead of hardcoded "QGroundContorl" strings

Changed Joystick._exponential from bool to float. It can now be set between 0 and -0.5 by user using a slider.

This makes VehicleComponents reusable from core plugin without
requiring override of prerequisiteSetup

This reverts commit 7131a12e.

* Fix minor spelling error

* Added support for the AUAV x2.1 Flight Controller
    also removed a duplicate entry for MindPX
    from src/comm/USBBoardInfo.json

Adds entries required to correctly identify, download and flash PX4
firmware to the AUAV X2.1 Flight Controller

* Update USBBoardInfo.json

Removed un-needed fallback entries. This has been tested!