Adding theme-color support
Merge branch 'material-sprint' of github.com:google/web-starter-kit into material-sprint

* 'material-sprint' of github.com:google/web-starter-kit:
  removed empty dropdown-menu.js
  dropdown-menu prototype, item code
  Modifying animation demo so it works in IE. Changes were needed because IE doesn't support calc() with CSS transitions.
  Fixes to animation demo: - Moving demo further down the styleguide - Code style fixes
  Fixing SCSS compilation issue after removing old sidenav code
  One ripple to rule them all. Refactors buttons, FABs, radio buttons and checkboxes to all use the same ripples. Also simplifies adding ripples to components by specifying the RippleEffect class (which is now required for checkboxes and radio buttons as well, which will otherwise not have ripples).