Renamed "Invalid" (airspace) to "custom"

The "Now" button now sets a "now" flag instead of adjusting the start time. Once the flight is created, the actual "now" time is set for flight start time.
The button is also exclusive. Once set, the start time slider is hidden as it becomes irrelevant.

If briefing evaluation returns no authorization, assume none is required. This is reflected in the UI as "Authorization Not Required".

Added some basic color management for airspaces

Change Command only supported for Simple Items

Prompt for Reboot after compass cal

Respect app units

Use NaN to signal lower level error

Kick off terrain query after load

Don't query intermediate state

Better logging

Add new Help page under Settings

Persist tile info as doubles. This prevent float/double precision match errors at the edge of tiles.

Bump terrain tile version due to format change

Turn internal errors (elevation == -1) into failed query to prevent bogus elevation from reaching upper layers.

Fix failure handling

Use qCWarning for internal errors

Save camera settings

Wrap text

Remove WIP

Fix editor sizing

Add control to set flight duration (which ultimately sets the end_time of flight)

Handle flight start/end time
Handle start/stop traffic monitor
Only start telemetry if enabled
Added a "Now" button for the flight start time
Collect advisories only when the rules change

Work around android Qt bug where wrong virtual keyboard is displayed

Fix negative wind direction

Fix initial value calculations

Add flickable

Add file extension if needed