Moved Actor-related fields to ItemWrapper
ItemWrapper unfortunately remains a field within Item (see #91)
Renamed INSTORE and created Item#flags2 field to track riiablo item flags
Added support for distinct vendor inventories
No inventory component yet -- generated each time vendor loaded
Moved VendorPanel inventory management to Npc for time being (from UI to a system)
Modified VendorPanel#config signature to include inventory item list
Created VendorGenerator#generate(String) to generate an inventory for a specified vendor
Added ItemGenerator and VendorGenerator systems to various engines
Created vendor generator which uses reflection to access item data and generate items
Added stub item generation for armor and weapons
Changed visibility of ItemGrid#addItem to protected (from public)
ItemGrid#addItem vis will revert when drain function is moved up class hierarchy
Modified signatures of VendorGrid#place* methods and function
VendorGrid#place* now returns boolean if the item can be placed
VendorGrid#place* stores available coords in input coords parameter
Added columns for base item vendor entries and noted issue with hratli
Added Excel#getEntryClass to retrieve the entry class type via reflection
VendorPanel populates tabs using "akara" columns
Added basic support for VendorPanel VendorGrid items
Added very basic ItemGenerator class to create Item instances
VendorPanel tabs now support distinct grid objects
VendorPanel will display the grid for the active tab
Added basic sort and layout function in VendorGrid to place items
VendorPanel MISC tab has sample data injected
