Added air and temperature constants.
Added unit conversions.
Added WGS84 constants.
Moved world magnetic model constants to physical constants file.
Replace sqrt( by sqrtf(.
Added copyright header and changes equation spacing.
Merge pull request #402 from kubark42/phys-constants-2

Phys constants 2
Refactor airframe configuration module to use enum values instead of
combobox strings. Also refactored UAVObject data calls.
Use only enum type for airframetype variable.
Simplified vehicle ui configuration slot.
Renamed refreshWidgetsValues(int), since it was completely different and
yet similarly named to the refreshWidgetsValues(UAVObject*) parent method.
One last uint16_t-> enum that didn't get caught.
Merge pull request #417 from kubark42/refactor-airframe-plugin

Refactor airframe configuration module to use enum values instead of combobox strings