Implemented normal EXT-7002 (Inventory flat list needs optimization.):

 - changed the LLInventoryItemsList::addNewItem() to add item to the list without immediately rearranging
 - implemented LLFlatListViewEx::setFilterSubString(), sets up new filter string and filters the list.
 - implemented LLFlatListViewEx::filterItems(), filters the list, rearranges and notifies parent about shape changes. The list items are filtered using the notify() functionality, without need in adding/removing them on each filter call. It sends 'match_filter' request to items and interprets the returned zero as sign of matched filter string, i.e. we don't hide items that don't support 'match_filter' action(separators etc).
 - filtring of LLOutfitsList.
 Reviewed by Mike Antipov at https://codereview.productengine.com/secondlife/r/342/

--HG--
branch : product-engine