First round of opcode fixes, added logger output to log file (.vnes.log)

Fixed Stack_Pull (stack pointer was decrementing instead of incrementing.)
Fixed Do_Add's FLG_NZ (need to cast the result to u8 before testing).
Fixed PHP instruction (processor status is OR'd with FLG_BRK before pushing.)
Fixed PLP instruction (pulled status needs FLG_BRK unset.)
Fixed Zero-Page wrapping for IX addressing mode.