Add Playable column for City-States in XML

Author: RecursiveVision

CvGameCoreDLL_Expansion2/CvMinorCivAI.h

@@ -956,6 +956,8 @@ class CvMinorCivInfo : public CvBaseInfo
 	CvMinorCivInfo();
 	virtual ~CvMinorCivInfo();
 
+	bool IsPlayable() const;
+
 	int getDefaultPlayerColor() const;
 	int getArtStyleType() const;
 	int getNumCityNames() const;