Simple vec2 implementation

For whatever
Moving the submap-grid into its own struct, the `struct reality_bubble`

It handles all the events and rendering itself so the game object is now
much leaner and cleaner
Improving the window resize handling

Now when the game is 'idle' (ie. between key-presses) we wait in 100ms
increments. Between each increment we break away from waiting
momentarily to check if the window has been resized. This section could
be used in the future for other things, I imagine, like processes that
need to be spread out over time for performance reasons, etc.