configuration: update JSON object to 2.0.15-rc4
Link Manager: Move LoadSettings to a timer
Install Firmware: trigger port scan after 1s
Waypoint List: Fix #507, waypoint save dialog saying "open" instead of "save"
Comms: Fix #486, added a custom baud rate option, as well as fixing issues where the window would sometimes be behind the main window
Map Widget: Fix #483, adjusted waypoints so they use absolute index rather than relative, allowing for easier understanding of what waypoint corrosponds to which item in the waypoint list.
Maps Widget: Update Google MAPs API
build: ignore stash file
Action Widget: Associate Shortcuts with Meta+SHIFT &RTL/&Loiter/&Stabilize

This requires the Actions Tab to be selected.
Upgrade to SDL2
Revive joystick code -- more of a re-implementation really.

Configure your joystick through the joystick menu.
Activate the joystick (so it sends events to the UAS) by clicking on the joystick name.

If the UAS is a multi-rotor in stabilize mode, the joystick controls are sent as RC overrides, otherwise if the UAS is in manual mode the joystick controls are sent as manual controls.
oopsy
Fix button pressed events not showing up in the UI
only emit joystickChanged at 10Hz if the joystick hasn't actually changed
oops: reversed Pitch&Roll
don't use operator!() which isn't present in Qt5
Merge branch 'joystick' of ssh://github.com/nbrachet/apm_planner into joystick