Small addition to the area doc.
Combined room_commands and object commands.

Removed room_commands, kept the function names related to room_commands
and have them call their respective object_commands.  They could also
be completely removed without doing any harm, they are not used
anywhere after this commit.  Also fixed some bugs in the check command
in the process of making it compatible.
Merge branch 'master' of https://github.com/nullinfinite/gurbalib