1.3 by Martin Pahl

 o Removed Timer::pulseImmediate() and
 o Fixed Timer::pulse(). A pulse should be send immediately, not after a
   delay. So I think, it's a bug in the original pulse function and there is
   no need for another pulse function.
 o Added optional callback functionality to Timer::oscillate (the version with limited
   repeatition) and Timer::pulse(). The callback function is called at the end
   of the pulse or oscillation.

Signed-off-by: Martin Pahl <pahl@tnt.uni-hannover.de>