Lab3 Sequencer

This is one of my labs for college. I like making music so I thought I'd have a go at making a small drum machine.
The code needs improvement:
The timing is not accurate.
The BPM button doesn't work.
The track play/mute buttons don't work.
and the code is a bit sloppy at the best of times.
Feel free to download and add these features, I will return to this later this year, but for the moment I'm finished.