mem,loadUnit_s2: let io.out.valid when exception occurs

RS: divide rs into three part: select & ctrl & data

Ftq: save pc and branch infos by fetch packet

Wrap data in Data8Module

L1 DCache Finished

IntToFP: opt timing

ifu: reconsider prediction of prevHalfInstr
     now we do not need to gather meta from the last packet
     because we update with packet, thus updating in the
     correct slot

Opt sbuffer timing