First update

Woah it's the first update.
Well, basically this update contains minor improvements.

• In the main menu added a light and the character will shoot to it automatically.
• Added animation of damage to lights when hit by a bullet.
• Added used music to the about section.
• Added music in the credits.
• The pause menu will not appear in the main menu.
• Workable sounds in options.
• Added more smooth transitions.
• Added Linux and web builds. (Just in case, windows and linux builds are 64-bit)