Portals and others

+ End and nether portals with configurability
+ Bed homes
+ Cauldrons fill
+ Added time and weather saving
* Various fixes, fixed #1066.

Portals don't delay properly or construct/search for a destination portal yet.
What does this line do?

If it's a biome that can't rain, or it's raining.. Seems a bit useless to me. 

Would this be a candidate for replacement by the new downfall functions?