Update/Fix JA2 vanilla

- added UB-tilesets to allow to use them for JA2 maps in JA2 vanilla as well
(follow up to previous commit)
- added missing "Alternative_IMP_Creation" entry into Data/ja2options.ini

Data/Ja2_Options.INI

@@ -184,7 +184,7 @@ USE_EXTERNALIZED_ENEMY_ITEM_DROPS = 0
 ; Valid values = TRUE or FALSE, Default = FALSE
 ;------------------------------------------------------------------------------------------------------------------------------
 
-USE_XML_TILESETS = FALSE
+USE_XML_TILESETS = TRUE
 
 ;------------------------------------------------------------------------------------------------------------------------------
 ; Change the number of PItem graphics files used by the game
@@ -197,8 +197,54 @@ USE_XML_TILESETS = FALSE
 
 NUM_P_ITEMS = 3
 
-; should mercs use the backgrounds 
-BACKGROUNDS = TRUE
+;******************************************************************************************************************************
+;******************************************************************************************************************************
+
+[Backgrounds]
+
+;******************************************************************************************************************************
+; These settings govern mercenary backgrounds.
+;******************************************************************************************************************************
+
+;------------------------------------------------------------------------------------------------------------------------------
+; If TRUE, mercs have backgrounds.
+;
+; Backgrounds can add a range of bonuses, penalties, abilities and more.
+; Some of those are merely flavour, others are significant for making full use of some 1.13 features.
+; Default: TRUE
+;------------------------------------------------------------------------------------------------------------------------------
+  	
+ENABLE_BACKGROUNDS = TRUE
+
+;------------------------------------------------------------------------------------------------------------------------------
+; If TRUE, choices in skills/character traits/disabilities determine available backgrounds during IMP creation.
+;
+; - don't show backgrounds in selection whose tags would contradict with a main bonus/penalty gained by previously chosen
+;   skill/character trait/disability
+; - gain additional background choices to make up for the possible loss in variety
+; - those additional backgrounds are exclusive to this option (and the sub-option REDUCED_IMP_CREATION), won't show up without
+; - the additional backgrounds are also affected by the same rules as all others
+; - this will only affect IMP backgrounds
+; - for more details see Backgrounds.xml
+; Note: requires ENABLE BACKGROUNDS to be TRUE 
+; Default: FALSE
+;------------------------------------------------------------------------------------------------------------------------------
+
+ALTERNATIVE_IMP_CREATION = FALSE
+
+;------------------------------------------------------------------------------------------------------------------------------
+; If TRUE, only use a reduced set of IMP backgrounds.
+;
+; - only use the additional backgrounds from ALTERNATIVE_IMP_CREATION	  
+; - by default, that's considerably fewer than the usual amount of background choices, but should cover some essentials
+; - same consequences from choices in skills/character traits/disabilities as with ALTERNATIVE_IMP_CREATION
+; - For more details see Backgrounds.xml
+; - this will only affect IMP backgrounds 
+; Note: requires ALTERNATIVE_IMP_CREATION to be TRUE (will show no effect if not)
+; Default: FALSE
+;------------------------------------------------------------------------------------------------------------------------------
+
+REDUCED_IMP_CREATION = FALSE
 
 ;******************************************************************************************************************************
 ;******************************************************************************************************************************