Plugins: refactored out unnecessary datastore constructor argument
Core: Make core object available at the module level
Plugins: Added TemplateDataProvider plugin interface

This lets you provide variables to the top-level namespace of
templates in a more seamless way than through a Connector plugin.
It's mostly useful for TemplateHelper for now, but may find other uses
in the future.
Core: Better stringification of server core objects
DB: fixed how Django settings are loaded
fixed Core stringification
Core: Avoid unnecessarily reparsing config file on startup
bcfg2-reports: rewrote with new option parser