Walk

Added walking sound.

Formal Version

First 120 sec won't spawn enemies.

Day-Night State

Fixed day-night state is not reset when game restart.
Change day time from 90 sec to 120 sec.
Change night time from 70 sec to 90 sec.

Optimize code

Optimize resource loaded and code.
Delete unnecessary code.

Particle

Fixed particle too less.

Release version

Just like title.