Billing block not shown consistently, easier report filtering on memberships

The May 2, 2014 changes were worked on during the code sprint. It solves the issue where the billing block is not shown consistently. 

The June 14 change makes it very easy to have report filters on membership organizations and/or membership types, following the existing structure for easy filtering on groups and tags.

See JIRA issue: https://issues.civicrm.org/jira/browse/CRM-14857