Improved interpreter

Fixed some registers being in big endian (fpscr, cr, xer).

FPU now now longer uses singles and calculates everything in doubles,
this is because a real powerpc cpu is meant to magically know if a
register is in floating point or double form, we will use doubles
everywhere and convert to/from single on load/store.

Split interpreter instructions across files into groups,
alu/cpu/flow/fpu/load/store.

Added stubs for unimplemented instructions so I can see my progress, 57
more instructions to go (for PowerPC cpu/fpu support, still need any
specific xbox360 instructions or vector instructions).

Upgraded project to vs2013.