v0.5.0 smoothing out performance

Some more subtle changes this week, but they add up to some good polish. Here's the list:

• High scores are now celebrated when you finally end your run.
• High scores will be reset, as I've moved the storage from the regular data file to the encrypted one. There shouldn't be any resets after this.
• Director obstacles now keep their state on the game over screen, i.e. if you get a game over with vertical waves, the director will stay vertical.
• Obstacles spawn more smoothly now; they rise out of the screen and cast their shadow further as they do.
• Upward waves don't have the weird banding anymore.
• Particle system optimizations on mobile. This mostly means fewer and bigger particles to reduce draw time

This week I'll be prepping the Google Play release and *making a trailer*--finally! So yeah, the plan is July 1 the game should be public up there. Tell your friends! After that it's Steam, and then iOS. It's official. It's happening! Thanks for playing!