Several x87 fixes, cleanups:

Several x87 fixes, cleanups:

- typedef unsigned char vfp_liveness, to make code easier understandable
- sim_binop:
    - Add a few comments and move code around to make it easier to understand
- sim_store:
    - Don't forget to create an fxch for mode_E fstp
- sim_fCondJmp
    - Add a few comments and move code around to make it easier to understand
    - comrs already reverse Jumps, no XCHG needed
    - test for op == 0 not op1 == op2 after fxch
    - assign results to the correct register slots!

- No need for block schedule anymore, fill worklist with successor blocks
- Get liveness from birg and don't recompute