This update implements following improvements.

1. Original submission required minor modification to RC4_set_key, which
   we don't want to tolerate and therefore we fix assembler instead.
2. Eliminate remaining byte-order dependence [look for RC4_BIG_ENDIAN].
3. Eliminate logical error [when key->x is referred prior key is verified].
4. HP-UX assembler puked on MODSCHED_RC4 macro with "syntax error,"
   macro has to be splitted in two.
5. Deploy parallel compare in function prologue.
6. Eliminate redundant instuctions and nops.
7. Eliminate assembler warnings.