First pass at BP_Component class. Refactor Activity component to use BP_Component. Introduce page templates for root directories. Rename bp-activity-templatetags to bp-activity-template per WP coding standards. Split bp-activity up into smaller parts. Introduce get_slug functions for activity component. More refactoring to do on other components. This will temporarily break trunk while refactoring happens, so be sure to pin to the previous revision if needed.