Don't override optimisation level flag, instead choose Debug / Release etc.
More reliable and cross platform way to seed RNG in test suite.
Add RTCM message type 1002 encode / decode and tests.
Decrease number of random test cases for coord system and lin alg.

Was taking way too long.
Linearise Sagnac rotation for speed boost. Tidy up comments in PVT.

Saves 4 trig lookups and a bunch of multiplies, only add <1mm error to the sat positions.