Cleaner counting for a second

I think this works?
Update lab2.asm

I think we were pushing r28-29 instead of r26-r27 in Timer0
Fixed up prologue and epilogue for Timer0
Renamed some counters
Removed a random ldi temp, 0
Improved readability
Merge pull request #2 from Glowx13/patch-1

Cleaner counting for a second