Improve layout for small-screen devices like phones

I tried NetTTS on Samsung Galaxy S2 which has pretty big screen for a phone, but it still had various layout issues, like "Save and restart" button going beyond right side of screen, with only "Sa" visible. On a modest QVGA device, NetTTS probably wouldn't be usable at all. These changes improve layout for small-screen devices, while hopefully minimally affect tablets (well, I had to remove font size overrides, but that's price to pay to let it display well on nay device).