Add DB module

	modified:   .gitignore
	modified:   ncebs/NginxConfEditor.py
	modified:   ncebs/api/domains.py
	new file:   ncebs/db/__init__.py
	new file:   ncebs/db/api.py
	new file:   ncebs/db/base.py
	new file:   ncebs/db/sqlalchemy/__init__.py
	new file:   ncebs/db/sqlalchemy/api.py
	new file:   ncebs/db/sqlalchemy/models.py
	new file:   ncebs/test/interface.sh
	new file:   ncebs/util/importutils.py