Implemented by SL EXT-6722(normal task) - Create modified inventory view for "my outfits" tab in top-level appearance sidebar (tier 1)

llui:
- Setting container panel for accordion tab control to dynamically add tabs to accordions.
- Added method to dynamically remove accordion tabs.
- Added LLIconCtrl image setter.

newview:
- Class LLOutfitsList - a list of agents's outfits from "My Outfits" inventory category which represents each outfit by an accordion tab with a list of items inside it.
- Class LLWearableItemsList - a list of wearable items used in each accordion tab of "My Outfits" tab.
- Class LLInventoryItemsList - a base class for LLWearableItemsList that represents inventory items by panels in LLFlatListView.
- Class LLPanelInventoryItem - inventory item representation for a flat list. Item icon is set according to item type.
- Class LLInventoryCategoriesObserver - an observer used in LLOutfitsList for monitoring changes to "My Outfits" inventory category and updating outfits accordion tabs and list of items for each outfit.

Known issues:
- Only first outfit tab is displayed in "My Outfits" until this tab is expanded.
- Bottom bar buttons and filter field not functioning for "My Outfits" tab since LLOutfitsList still doesn't support selection, filtering and sorting.
- "My Outfits" and "Wearing" tabs of "Appearance" side panel might need a common interface to use LLOutfitsList and LLinventoryPanel as tabs in LLPanelOutfitsInventory or "Wearing" tab should be replaces with LLOutfitsList class object i.e. a flat list.

On review - https://codereview.productengine.com/secondlife/r/285/

--HG--
branch : product-engine