Appearance update

Added tabbed section to controls input (functions, loops, constants) as
basis for further work. Also set position to fixed, and fixed resulting
bugs.

No javascript has been changed; functionality should be identical to
previous.

Next few steps:
-Add remaining buttons
-Update button layout
-Add functionality to buttons (array)
-Add functionality to run (array->arduino cmd)
-Add ability to move and/or delete elements in array/list