bashrc: Add alias for mplayer with common options for playing music

These music options mimic the conditions of music played by awp
populate-usb: Allow PLAYLIST env var to override default
awpmerge: Simple CLI tool to merge awp playlists
Shortcut script for mikeirc client
countdown: Fix bad timing code that would lose time

sleep 1 for N times is NOT the same as sleep N.
Time was running long by approx 1%
New method directly compares current time to start time.