Avoid having scrollbar on main view with 320x480 display (eg: Keon)

This PR replaces #41 

This one is a small cosmetic change. On my Keon, the main page (with the start button) can scroll by a few pixel. This PR makes the main page fit into view without scrolling bar


note: I think that if you set the develop branch as default (in your repo settings) forks and PRs should automatically default to the default branch too