Changes for v0.91

Edit:

D'oh! Forgot debug mode active, game started immediately at stage 25. Fixed this with v0.91_fix

A few quick changes for v0.91.

- Removed a safe spot and a laser collision box that was missing, for stage 25.

- Added a secret Easy Mode, for practice. It can be accessed by holding Left when starting a new game. However, the player won't be able to save any progression or highscores.