4 lane timing capability

This one I wanted to save for release 2.1, because with the way SRM2's timing routine was written, it would cause too much slowing down to check all 4 lanes reliable. But: every time an HO racers was interested in SRM2, he asked me if 4 lane timing capability was available. So, I rewrote the entire timing routine, which now checks all lanes on BIT level, and even managed to write a faster routine WITH 4 lanes!
While doing this, I also rewrote the hardware lane value checking routine (to store the values for each lane the first time you use the program), which is much more user friendly now.