Suprise!

This was supposed to be done some time in the last year. The update adds some nice new skins, adds some nice to have things and most importantly 9 new levels at the end of the game. Most of the new levels involve loops and feature spaces that transform to open new paths (off vs spinning fan for example) to explore some level designs that feel different enough to warrent another full pack of levels.

Changes

• added new 5th level pack (Exhaustive Detour)
• added new "challenger", "burnt", "space", and "rage quit" slime skin
• added new menu music for when the game was beaten
• added credits sequence
• remember last selected skin in selection
• fix loadscreen always showing the next level number
• fix spike ball spawner idle bug
• fix some music play/silence bugs