Add Room(Node) constructor

Resolves #27.
Add Roomstate(Node) constructor

Resolves #28.
Update Room XML

Added the shortdescription and longdescription nodes to the roomstate
node.

Pulled "key" nodes out of "roomkey" node, and instead used "roomkey"
nodes.
Merge branch 'master' of https://github.com/phoenixfyre/UtopianEngine