- Allows use of hardware floating point on the Cortex-M4.
- Added "f" suffix to floating point literals.
- Call floating point versions of stdlib math functions.
1. it's step towards rearchitecting the current code base ahead of a move to RTOS.
2. internally it uses a MatrixTable for the Quad, Octa, OctaQuad, Y6 frames.
3. it implements the missing stability patch for Octa and OctaQuads (still missing for Y6)
Later check-ins will incorporate into the main ArduCopter code.