MainWindow: set minimum size to 640x400

Signed-off-by: Koen Kooi <koen@dominion.thruhere.net>
Merge pull request #627 from koenkooi/vgascreen

MainWindow: set minimum size to 640x400
Merge pull request #635 from mavlink/keyboardshortcuts

make keyboard shortcuts OS dependent
Merge pull request #644 from Susurrus/mission_protocol

Mission protocol refactoring
Merge pull request #636 from mavlink/stream_rate_config

Added support for stream rate config to MAVLink inspector. Allows to con...
Protect against empty lists, fix map interaction
Merge master