moving urbansimd to usui

It was decided that urbansimd should not live in urbansim, but should live with the website repository instead.  It brought in a number of dependencies that don't really apply to the general population of urbansim users.
Merge pull request #29 from synthicity/move-server

moving urbansimd to usui (deleting from urbansim)
Initial Sphinx organization.
Barebones pages for urbansim.models modules.
Barebones pages for some urbansim.utils modules.