Updates to UI

Updates to UI to remove mouse requirement and use of "unity UI" buttons.
Now using (placeholder) drawn buttons, and keyboard input to interact
with various menus. In game pause menu is styled the same as main menu
using a flying wasp as a cursor (while everything else is paused). On
victory/failure, new onscreen messages and pressing R restarts level at
this point.

Some work started on player sprite to indicate taking damage.