Drop commented out icon setup - we will use font icons
Merge branch 'material-sprint' of https://github.com/google/web-starter-kit into material-sprint

* 'material-sprint' of https://github.com/google/web-starter-kit:
  Drawer button changes for Layout module: - Changing default behaviour of drawer buttons to push down the content, instead of overlaying on top of it. - Adding optional .Layout--overlayDrawerButton class to allow previous behaviour. - Switching layout demos to use .Layout--overlayDrawerButton. - Tweaking layout for index page.