Use Material UI; improve Preferences Page

New principles for our UI:

- Components should use inline styles whenever possible
- Let's shrink the size of main.css to < 100 lines over time so it just
contains typography and basic styles
- Always require just the individual component that is needed from
Material UI so that the whole library doesn't get loaded (important for
startup perf)

package.json

@@ -18,7 +18,6 @@
     "application-config": "^1.0.0",
     "bitfield": "^1.0.2",
     "chromecasts": "^1.8.0",
-    "classnames": "^2.2.5",
     "create-torrent": "^3.24.5",
     "deep-equal": "^1.0.1",
     "dlnacasts": "^0.1.0",
@@ -29,12 +28,14 @@
     "iso-639-1": "^1.2.1",
     "languagedetect": "^1.1.1",
     "location-history": "^1.0.0",
+    "material-ui": "^0.15.4",
     "musicmetadata": "^2.0.2",
     "network-address": "^1.1.0",
     "parse-torrent": "^5.7.3",
     "prettier-bytes": "^1.0.1",
     "react": "^15.2.1",
     "react-dom": "^15.2.1",
+    "react-tap-event-plugin": "^1.0.0",
     "run-parallel": "^1.1.6",
     "semver": "^5.1.0",
     "simple-concat": "^1.0.0",