Some more UI updates and fixes.

* Added UICreatureButton class for handling/replacing "battle buttons" (can now be used in other modules).
* Added the ability to use items on creatures via the battle window.
* Some minor cosmetics.

modules/game_market/market.lua

@@ -154,6 +154,11 @@ local function clearFilters()
   end
 end
 
+local function clearFee()
+  feeLabel:setText('')
+  fee = 0
+end
+
 local function refreshTypeList()
   offerTypeList:clearOptions()
   offerTypeList:addOption('Buy')
@@ -165,11 +170,6 @@ local function refreshTypeList()
   end
 end
 
-local function refreshFee()
-  feeLabel:setText('')
-  fee = 0
-end
-
 local function addOffer(offer, type)
   if not offer then
     return false
@@ -841,7 +841,7 @@ function Market.resetCreateOffer()
   totalPriceEdit:setValue(1)
   amountEdit:setValue(1)
   refreshTypeList()
-  refreshFee()
+  clearFee()
 end
 
 function Market.refreshItemsWidget(selectItem)