COORD_SYSTEM: Adding degrees-to-radians functionality and consistify-ing the types of conversion functions
COORD_SYSTEM: Using predefined D3R rather than doing GPS_PI/180
COORD_SYSTEM TEST: Test the degrees to radians function against the north pole, and against swiftnav office location
Switched from CamelCase to underscores
CONST CORRECTNESS: Fixing linear_algebra matrix inverse. const TYPE *const NAME
Merge pull request #24 from njoubert/fix_const_correctness

CONST CORRECTNESS: Fixing linear_algebra matrix inverse. const TYPE *con...
Merge pull request #23 from njoubert/coord_sys

COORD_SYSTEM: Adding degrees-to-radians functionality and consistify-ing...