Complete subworlds test 1: world in building

-Only two layers of depth (not recursive)
-Testing view: Left plane is the bigger one
-Functions cleaned, renamed, commented
-TODO (in the next few minutes): restore first person view
Complete subworlds test 1.

-Building inside building (2 layers total, no recursion).
-Code cleaned/commented.
-TODO (shortly): Restore first person for full test.