[0/1] Let's go float!

Changes:
1. Move uint16 -> float conversion from always-on temperature iop to new always-on letsgofloat iop, which is supposed to be first-one in the pipe.
This allows Invert iop (and all further new iops) be float -> float, not uint16_t -> uint16_t --- better quality
2. Fix issues created by this move.
3. Implement OpenCL kernel for letsgofloat iop.
4. Fix issues created by this move.
5. Implement OpenCL kernel for Invert iop.