ENYO-690: Add media queries for setting root size.

### Issue
We need to set the appropriate root `font-size` based on the screen resolution.

### Fix
We use the appropriate media queries to set the `font-size` of our `html` element.

### Notes
Travis is expected to fail as the generated CSS will not be the same as what Travis expects due to the changes we made for compiling LESS.

Enyo-DCO-1.1-Signed-off-by: Aaron Tam <aaron.tam@lge.com>