MFC 198696
MFC 198696

    Cleanup in r600_blit

     - Don't bother to assign vb until we know we have enough space
     - Add variables for sx2, sy2, dx2, dy2 so that these aren't
       calculated over and over, also reduce chance of errors.
     - Use switch to assign color/format

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase