A general bug fix and balancing update

Fixed an issue in endless mode where you couldn't use the shotguns right click after unlocking the bug zapper

Fixed multiple audio issues with the bug zapper

Fixed an issue where the music in endless mode would continue playing after you die

Buffed the damage of the un-upgraded shotgun

Made mulch in endless mode spawn less often

In wave 3 of normal mode, the bug spray's right click gets a cooldown decrease

A Water Bug spawns in wave 3 now

Changed the sprites for the Water Bug, Mosquito tire, and Larva spawner.