Design

This branch has design for controls and all the things I broke in the name of design. It's not ready for merging, but I don't know how to fix it so I'm pushing it for you to see. 

The main sequence page should only have the original control elements (Tempo, Play, and the time), but because I wanted to group all possible controls in a single row, all of the options are showing. I moved the controls from part.handlebars to application.handlebars so I could mock them up and this subsequently made things stop working, oops.

The play bar indicator, play/pause, time aren't working, but you can hear the sequence.