New modifiers for Item Properties

The new Item_Settings.ini is there to host modifiers for item properties in the different XML files. For now it is only used for the Weapon Overheating feature to adjust parameters based on gun class.
It uses the new struct gItemSettings which is populated in function void LoadItemSettings() on game start.

git-svn-id: https://ja2svn.mooo.com/source/ja2/trunk/GameSource/ja2_v1.13/Build@6463 3b4a5df2-a311-0410-b5c6-a8a6f20db521

gameloop.cpp

@@ -134,6 +134,8 @@ BOOLEAN InitializeGame(void)
 	LoadCTHConstants();
 	//DBrot: load mod settings
 	LoadModSettings();
+	// silversurfer: load item settings modifiers
+	LoadItemSettings();
 
 #ifdef JA2UB
 	LoadGameUBOptions(); // JA25 UB