Added fixes for a few CSS things that were bothering me.  Not everything I intended to fix is fixed, but the buttons are more centered and look more Material, and I added a proper button (hack, hack) for file upload.  I also removed instructions from the html, we need a better place for this.  It's commented out, not removed.  I'm thinking it should be implemented in a popup that shows on first-time startup, but could be re-shown from a help button.