Feature phone improvements

[jakearchibald]

• add push state for (device default) back btn #412 Fix back button (clashes with soft keys).
• Things that appear in the bottom left or bottom right clash tend to clash with keys next to the screen. We should look to move these unless we can make the keys work.
• Ensure all buttons work like buttons.
• Remove logo from start page for feature phones, so the start button is more visible.

[kosamari]

adding item

• focus goes invisible on start screen
  (my hunch is that some element is "focused" but not showing focusring.)

[jakearchibald]

focus goes invisible on start screen

I wonder if it's the up-down buttons on the selects

[jakearchibald]

It was. I've removed them at feature phone widths.