0.2.0 -- Rebound mechanic & progression

This update adds a few gameplay tweaks:

• There’s now a title menu, though the only mode is still Endless Mode.

Progression:

• Progress in Endless now proceeds through a number of deterministic levels before switching to a procedurally generated layout.
• The size of the board will zoom out to fit larger levels, though playability of later levels is still dubious.

Active Rebound:

• The “juggle” mechanic is now “Active Rebound”. When you destroy a target, it will activate, allowing you to grab the shot and re-fire it. In this mode aiming is predictive instead of motion-based (like a pool or golf game).
• If you rebound the shot below the rebound line (bottom of the screen), you will rebound with 1 bounce, instead of 0.

General shot mechanics:

• I’ve removed the restrictions on where you can shoot from.