Portals and others

+ End and nether portals with configurability
+ Bed homes
+ Cauldrons fill
+ Added time and weather saving
* ~~Fixes #1066~~
* Fixes #1012, fixes #1194

Portals don't construct/search for a destination portal yet.
Somewhat unclear description. How about "Set to a valid world pointer by MoveToWorld; reset to NULL when the entity is removed from the old world."?
No need for the "Can't be a simple boolean", that part of the logic should be documented in the MoveToWorld function, not here.