Fix failing tests.
Move some system events into respective modules.
Add #show_cursor and #hide_cursor commands to Cursor.
Add methods from Position to Cursor;

- Add default values for top and left.
- Position is starting to become redundant.
Update Cursor;

Use the interface's geometry for basis of position.
Prefer $LOAD_PATH to $:.
Handle Fixnum as a defined value.
Don't need this anymore.
Add more documentation.
Remove `cursor` from interface API, also;

- Add Cursors class to track position and visibility of all interface cursors.
- Move Cursor into models/.
- No longer render the cursor as part of an interface refresh.
- Refresh cursor when interface focus changes.
- Refresh cursor for focussed interface when terminal resizes.
Add basic 'cursor_app' to demonstrate cursor usage.
Add name to Menu instance, also;

Defer building of collection into a Menu object until we store the menu.
Add more documentation.
Prefer single quote for strings without interpolation.
Uncomment previously failing tests and fix them.
Remove redundant tests.
Add test for Cursors in Registrar.
Make example cursor app a little more interesting.
Move KeymapValidator to support/
Add more documentation.