Bug 1024893 - [dolphin][v1.4]Entering settings app takes more than 2.2s

This patch reduces the Settings startup time by more than 1.5 second on Flame by doing several things:

- Load `root` list inline during build time, by removing the dependency on the JavaScript chain that does it dynamically. This way we don't have to wait for JavaScript to do that, and the settings list is ready right away.
- Removes `link` elements that are meant for tablet only during the build process, because it spent a lot of time (more than 200ms) executing the media query code in there.
- Removed unnecessary background-color setting on the html and body elements (see https://bugzilla.mozilla.org/show_bug.cgi?id=1036446). Color is already set on the children elements anyway.

/cc @janjongboom