Updated RC Cal validation rules

Rules:
- Default min/max/trim settings are 1000/2000/1500
- A valid min setting must be below 1300
- A valid max setting must be above 1700
- If either min or max is invalid: min, max and trim will ALL be set to defaults
- Trim is only read from RC input for roll/pitch/yaw/throttle
- Trim for all other channels is calculated from center of min/max

These rules will cause channels which are above the currently available channel count (example: 8 channel radio, channels 9-18) to be default min/max/trim. They will also cause available channels for which rc input does not move to be default min/max/trim. For example 18 channel radio, with some channels only available via mixing.

Widget visuals:
- New display for invalid min or max

Unit Test:
- Updated to test all the above rules and new visuals

This fixes Issue #839