Create database and install PostGIS on services VM when in development
Install daemontools for envdir
Feed database settings into /etc/nyc-trees.d/env
Add prefix to port forwarding definitions for services

Attempts to resolve #35.
Rename database settings to nyc_trees
Pull database settings in from the environment
Install geospatial libraries so that management commands work
Setup port forwarding for runserver
Update README
Bump version of ansible-nginx
Wipe and install Ansible roles

The previous method to install dependent roles was not accounting for
scenarios where a role existed on the file system, but needed to be
updated. This changeset removes all `azavea.*` roles and then reinstalls
them.
wip
wip