Large polish patch - final testing looms!

Got around to setting up a #Gnomancer channel on the discords: https://discord.gg/JG2pbxC

Fixed a number of issues related to testing via Steam Play Together Anywhere, improving 2/3/4 player support, as well as situations where Pad 0 isn't the main player.

Added support for Steam Cloud

Health Collectables will now heal by percentage - 5 HP is a lot for a level 1 Wizard, but not for a level 500 Knight.

All UI elements should now have audio feedback. Especially difficulty settings.

Locked levels should now give specific hints about how to access them.

Tons of polish on UI enabling and disabling appropriately.

Reworked Gnome locations on Level 2 to better breadcrumb players through

Altered Level 6 to remove alternate routes, so early players are experiencing a more linear path.

Added more Gnomes to level 6 to make it completable with much less levelling - you shouldn't finish the level with thousands of dust and nowhere to spend it.

Improved Gnome stuck/teleport mechanics and effects mean a substantially lessened chance of nearby Gnomes getting stuck. They should also now warp through nullspace.

Alive Gnomes now give bonus XP at level end - this is correctly scaled by difficulty.

Gnomes with no owners will no longer take part in the physics simulation.

Press X prompt is now intelligent

Gnome Summon hides when you Pause

Escape now toggles pause menu

Load Ticks dropped from 80ms to 3ms because I had a brainwave.

Huge improvement to CPU usage of Map preperation.

Fixed skin selection to be sticky across all characters

Fixed issues with generating levels at low FPS being unreliable

Even more performance improvements to loading!

Fixed an issue where multiple accounts on the same computer would lead the progression system to using the slowest time, not the best.

Levels past the end of Early Access are available, but are clearly marked as unfinished.

Bonus XP is now colour-coded.

Tweaked script execution order, vastly improving instantiation spikes

Fixed issue where players could briefly attack after dying, messing up the animation system and looking stupid.

Added Low health/Damage effect. Only applies on Single player.