More Market fixes

* Fixed NextButton and PreviousButton style
* Little update to SpinBox including dontSignal
* Market cleanup and more check to be safe
* Limit Market amountWindow by player balance
* Set proper maximum amount when creating offers
* Fixed fee label not calculating the correct fee sometimes

modules/gamelib/market.lua

@@ -1,3 +1,8 @@
+MarketMaxAmount = 2000
+MarketMaxAmountStackable = 64000
+MarketMaxPrice = 999999999
+MarketMaxOffers = 100
+
 MarketAction = {
   Buy = 0,
   Sell = 1