Patch v1.0.3

Just minor tweaks and hotfixes, added a few things here and there since the jam release.
(List below may not include everything, just what I remember)

Changes:

• Added a texture for the background wall (which was a solid color);
• Added some particles for walking and jumping;
• Added a settings menu with audio volume sliders.

Fixes:

• Finally (or hopefully) fixed seemingly random crashes related to the gameover screen;
• Removed unwanted gray borders that appeared on fullscreen mode in the desktop version (Workaround);
• Fixed issue with enemies staying a bit too far from each other.