Initial Import

Work in progress, backend integration more or less done besides the
indexing.
Fixed a couple of bugs in the backend model and also added the indexer framework. Now only the indexer needs to work
First version of the indexer ready
Added some calls to Varien_Profiler
Move the splitting of the group id records into seperate _prepareRow() method
Clean up helper methods
Move _getIndexTable() method into abstract indexer class and fetch value from new helper method
Add Filter resource model and add collection load before observer methods to add filter logic
Moved mode settings application logic to helper, fixed bug in indexer to apply mode settings if applicable
Add alert if the mode configuration is changed to run reindex
Lots of reworking, now single loads of products and categories are filtered, too (regardless of the flat catalog setting)
Add category flat resource model rewrite to enable category filtering when the flat table catalog is on
Add getConfig method to helper
handle cache invalidation when visibility settings are changed
Add groupscatalog filter to the product count select fot the category navigation
Init resource to avoid exception when the flat category is enabled
Recollect totals once after loading in case a quote item product visibility changed
Fix comment to salesQuoteLoadAfter() method in observer
Reduce overhead keeping the quote item qty up to date in the salesQuoteLoadAfter event observer
Fix wishlist item count