Improve navigation via arrow keys

 * Prevent them from also scrolling the window, which was
   problematic when in a narrow window
 * Add ctrl+arrow to navigate between special frames and
   ctrl+shift+arrow to jump to beginning/end
Lower-casing "Frames", the uppercase broke things

On my machine, at least
Merge pull request #105 from cincodenada/master

Improve navigation with arrow keys, prevent scrolling window while navigating