Been using OTS AV DJ for a couple of years now... I use it 90% for the same purpose that you are looking for... Pre-show set up a playlist with automatic beat mixing for a seamless audio presentation... and post show I play a few dance songs so the clientele can dance, or the bartenders can cleanup to a beat... while I teardown the basics (mics, monitors, unnecessary wiring etc.)
This is an expensive piece of software ( I have two licenses @ $299 ea ), but I haven't used a better DJ program... I invest in Quality, and Hoster is in that category...
I will post a link that Admin can edit for business purposes.
http://www.otsav.com/