Pages are always maximized, browser size must be >= 1280 width

- The maximized enforcement is a bit of a hack, but will do for now.
  Preferably we'd work with mozwebqa directly to do this.
- The 1280 width might annoy people; if so, we can take it out.
  However, the appliance isn't supported at widths lower than 1280px,
  so it doesn't do much good for tests to be running below that rez.
Lint.
Merge pull request #230 from seandst/pages-width

Pages width check