Revert "aaaaaaaaa"

Just about everything in that commit was insane.
Prepare to merge relative sanity.

This reverts commit 3874e4a710d49c17dad9d94b25667f3355ed4ecf.
Rename Player to GEPlayer.

In preparation for separate, cross-world Player class.
Create separate, non-world-specific Player class.

Temporarily breaks world-switching.
Still seems much neater than other way.
Fix bug with invisible GEMGOs at start.

Exploredness wasn't being set early enough.
Optionally specify GEPlayer starting position.

Useful for teleporting.
Re-enable world-changing keys.
Re-enable portals.
Move ownership of world-surfaces to GEPlayer.

They're player-specific, and shouldn't exist anyway.
Async world loading, splashscreens.
Move GEMGO rendering, update() to rendervisible().

Allows rendering visible area without causing world tick.
Give destination coords to Portals.

Get teleported to a specific location!
Return of the lose condition!
Small tweaks.