Patch 0.3.0

Additions:

+ Levels now have checkpoints

+ Added hands to some weapons

Changes:

- All levels now use the spawning enemy mechanic that was introduced initially in E1M5

- Updated the character in the main menu to hold weapons

- Some levels have had layout and enemy changes

Fixes:

* Fixed projectiles not going through secret trigger zones

* Fixed projectiles not going through wall shields that are deactivating