v0.15 - More sounds and music updates

This release focuses on enriching the audio tapestry of the game. Essentially, it boils down to adding a lot of sounds where previously there was only silence. Plus, MaxStack has reworked his older work and added a couple more tracks to the game. The final addition is the About game window with credits. Changes: [list] [*]Around 50 new sounds [*]Music updates and two new music tracks [*]About game window [/list] Fixes: [list] [*]Disabled background ambience in new game menu [*]HUD fixes for multiple timeouts and timers [*]Fixes for mouse clicks on game view [*]Fix for area alertness stuck at the same value [*]Possible fix for rebirth exception [*]Fix for player entity on loading a region mode save [*]Fix for completing the uncover more events goal if the player stumbles on REDACTED randomly [*]Returned close button to main menu [/list]