New menu logo, lives, return to menu, ai collision fix

I'm chipping away at the remainder tasks to do before the Steam Early Access release!

Things added

• New menu logo
• Return to menu from in-game
• Lives system. You progress is saved until you lose all 3 lives, then you reset at the beginning of the level with 0 score.

Things fixed

• I think I have finally fixed AI collisions, where they would move outside the playable area. >.>

Things remaining before Steam release

• I think I will make one more level. Just so it's not a one-level game.
• Game cover logo and assets for promotion

I still am a bit poor at the moment, due to moving out and having to pay for necessities. So even if I get the new level(s) done, there may be some wait before it's on Steam :( But you'll get the updates here!