Try hard not to lose on time

We try hard not to lose on time even under extreme
time pressure. We achieve this through 3 different but
coordinated steps:

    1) Increase max frequency of timer events

    2) Quickly return after a stop signal

    3) Take in account timer resolution

With these SF played under LittleBlitzer at 1"+0.02 and 3"+0
without losing on time even one game.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>