Added sticky blocks

These blocks are the first of several that I plan to add in order to make the game more interesting and make for better levels. Whenever you run into a sticky block, you snap to its position and stop moving, while the level continues to rotate. Once stuck, you can launch yourself in any direction by pressing that key.

I decided to add these because I thought it would be cool to have levels where you launch yourself through a large number of sticky blocks, and they add a method of transportation other than the basic rolling and jumping.

I’m thinking about ideas for other blocks, and as soon as I have a few I’ll start to build some levels.