Make interpreter shared between Server and World.

World used to own it, which made a lot of sense in lots of ways, and
now it's a lot less pretty, but oh well. The Interpreter architecture
should have been different.
Client can upload subprograms.
Player has option to replace existing subprograms.

compile --replace
Made byte extraction check length.

also adjusted some delay values. And I have no internet and no coffee
so that's all for now.
Fix segfault on exit.

Used to delete world even if there wasn't one
Merge branch 'serverside_interpreter' into gui

Conflicts:
	src/server.cpp
correct moving mechanism coming tonight