Compost Airhockey Mode

This update most notably brings the tabletop fun of airhockey to the green thumb world of Compost. Lets just say the wind god was challenged to a game by the god of steam to a game of airhockey and this happened. It's quite fun, all the robots and bugs and plants came along for the ride, mostly to be violently squished by the pucks and paddles. It follows the same rules as wave mode. I tried to make some excellent paddle AI, it's eerily human-like! Other changes:

• Seeds that come in from the map edges. Necessary since the airhockey stuff squishes locusts and the seeds in their bellies, so this gives the possibility of greenery to airhockey. Whilst also increasing the plants that show up in classic mode.

• The boss robot has been revamped. It's a ticking time bomb of doom and constantly dodging.

• Shield robots changed from shield projectors to robots with an inflatable balloon system. They're happy to expand their balloon and block a projectile.

• Flowers grow at the end of a wave provided that there are butterflies available for pollination.

• Venus flytraps are now brutal. Any bug trying to chew on them should be afraid, but they don't like eating metal objects.

• Smog doesn't slow down the fps... as much!

• Many other tiny improvements.