NEW: Full window, resizable rendering
FIX: Title
REFACTOR: WorldCell is now a custom class
MINOR: De-linting
NEW: Add pre-rendered tiles

The pre-rendered tiles will be critical in ensuring adequate performance for large screens and zoomed-out
maps, but right now the interaction halts while new tiles are rendered.  A render queue is needed.
NEW: Add +/- keys for zoom in/out
NEW: Added queue for rendering tiles

This queue stops the screen from freezing, but currently the ordering of items on the
queue isn't particularly optimal.
NEW: Add random colours

This just makes it a bit easier to see what we're panning over