ad 6.x-2.1-rc1

New features:

• filter reports on ads not assigned to any channel
  #506512: Filter by <none> for channel in Ad List
• provide inventory for channels, allowing remnant ads to fill in missing inventory
  #487966: Remnant ads
• provide manual mechanism for flushing file cache
  #485236: Force file cache to rebuild
• display probability on ad overview page
  #485244: Add weight to Ad list

Bug fixes:

• document <front> as an acceptable path
  #511200: <front> not working on channel settings
• remove unnecessary object
  #491324: Ad view counting broken
• add missing ';' to properly display '<' in form
  #476480: Spelling error in ad_embed-module
• remove unnecessary call to ad_groups_list() (patch thanks to 'lonelyrobot')
  #480884: Unneccessary work done in ad_block() "view" op
• proper filtering by group and by both group and channel
  #485218: Filtering by Group AND Channel returns 0 results
• properly validate remote image, allowing it to be set as active
  #437580: Image validation failed, unable to mark ad as active. Setting ad as pending.
• properly cast db query so can filter on multiple nids or tids
  #453236: error on try to show ad related to more than one tid
• allow nodes to save properly on creation
  #436234: CCK nodes do not save on initial creation when ad_channel or ad_weight_probability is enabled
• be sure the file cache is disabled when the ad file cache module is disabled (patch thanks to Garrett Albright)
  #436926: File cache module not optional?