Added a Main Menu, a Speedrun mode, and optimized the game.

SpeedRun Mode:
Kill all the dummy titans as fast as possible. Currently, there is no scoring system and the mode is more of a practice on how quick you can be. I will implement scoring in a future update.

Optimization:
For optimization, there was a problem when switching levels. That problem was because there were an extreme amount of vertexes on them. An amount to crash the game while loading a level. That problem is fixed and it is now faster to switch levels.

For the Future:

My next goal is to add titans, improve the Speedrun mode and make the Main Menu better, and add a few more game modes such as a survive the waves or a little training mode to give the basics. Hopefully, if all goes well I should be able to release most of this sometime during the summer.