Use flip32 function instead of open coding it in gen_stratum_work.
Use flip helpers to simplify code for calculation of midstate.
Provide a flip128 helper to simplify big endian flipping.
Provide endian_flipX functions to avoid special casing big endian in cgminer.c
Use system host to endian functions for clarity in fulltest.
Fulltest is true if value is <= target.
Avoid one cgtime call in sole_hash_work.