Don't redo the DB if it already exists.

Fixes #8
Use a simple cp for configs instead of stow

Fixes most of the issues around nginx and symlinks

Configuration changes will now require reprovisioning.
Don't fail on creating directories.

If mkdir fails, it's probably because the directory is already here.
Clean up ecoservice provisioning

 - Don't download Go again if it is already there
 - Use godep for dependencies
 - Use the project's Makefile
Stop services if they are running at the start of provisioning
Don't fail when setting up nginx sites if it's already done
Merge pull request #17 from OpenTreeMap/reentrant-provisioning

Reentrant provisioning