Remove BEEP_INTERVAL between beeps
Remove BEEP_INTERVAL between beeps

The BEEP_INTERVAL of 1 second between beeps was introduced to make
consecutive beeps sound distinct while using the timebox script via
PuTTY. Without the interval, consecutive beeps sounded like a single
beep in PuTTY. The BEEP_INTERVAL was a workaround to this issue.
However, it was not a great workaround because the 1 second interval
between the beeps feels a little too long.

However, on Mac OS X, consecutive beeps sound like distinct beeps
without BEEP_INTERVAL. Therefore, get rid of the BEEP_INTERVAL
workaround. How to make the consecutive beeps sound like distinct beeps
in PuTTY (if that is possible) can be figured out and documented later.

susam/timeboxing