Slowed down safeGuard task

Overview
--------------

I slowed down the `safeGuard` task by adding a `wait1Msec()` call to every
loop. This allowes the NXT to spend more time dealing with your
engine, while still checking the encoder limits fast enough to stop
any out-of-bounds movement before the robot breaks.


Customization
---------------------

To tweak the delay, just change the `GUARD_UPDATE_TIME` global to the
desired number of milliseconds.