Support for default mission item altitude setting

ArduPilot: Load params from new Airframe page

Ignore heartbeats from non-default component

Handle ArudPilot parameter changes in newer firmwares

Auto connect on start for UDP links

Joystick Hotplugging

Fix position of children of complex items

DoubleValidator causing problems with regional settings

Changed default component id discovery

Causing data loss

Don't send EOS on pipeline if not streaming video

Experimenting with Video / Photo commands

Use component id from heartbeat

Parameter editor dialog mobile

Plan-Simple Item: Use all remaining width for text fields

Fix ComplexMissionItemText unit test crash

* 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!

Dealing with lack of Internet connectivity.