Namespace prefixes and project settings

Add get_setting() to settings.py and allow looking up config values in project data
Adjust import_namespace_command.py to use get_setting() and to add a prefix to namespaces if defined
Adjust utils.py to use get_setting()

Signed-off-by: Ronan <ronan@d3r.com>
Update CHANGELOG and README
Fix retrogression of previous PR - don't add \ to namespaces when there's no namespace prefix

Signed-off-by: Ronan <ronan@d3r.com>
Merge pull request #24 from ronanchilvers/master

Namespace prefixes and project settings