Bump version to 0.2

This is again mostly technical release, but I hope those changes will help me to focus on gameplay now.

• Menu refactoring, now we somehow can do menus without pain
• Input and event system improvements, but there much more work to do
• Abstract application framework was extracted into separate project (github.com/pkulev/eaf)
• Pygame stuff was completely removed including sounds
• Config files converted into TOML
• Terminal-specific application stuff was extracted into separate project (github.com/pkulev/xo1) with intention to reuse it for some projects later
• All sources were blacken
• Finally timers and clock work properly and application send dt into all updates
• Fixed some nasty bags including out of bounds passage

Nothing changed in gameplay at all

This is another hollow technical release, lmao.

MInimal working game experience

We've resolved many issues and added a bunch of features, such as levels, collision detection (thanks, @alex-eg), simple interpolated animations, score counting and game over screen.

That work showed us how difficult garbage collecting and message passing is in our system. It took many days to implement things that don't affect gameplay, and they are still working bad.

This release contains poor but working gameplay mechanics. To keep things clean I am reducing scope of milestones to doable within month or two.

Alpha Freeze Release

XOInvader is going to support pygame, thus this release will be the point of return and history milestone.
Wheeeee!