[cpp] Make Constraint and Posed pure

spine-cpp/include/spine/Constraint.h

@@ -52,9 +52,7 @@ namespace spine {
 
 		virtual void sort(Skeleton &skeleton) = 0;
 
-		virtual bool isSourceActive() {
-			return true;
-		}
+		virtual bool isSourceActive() = 0;
 
 		// Inherited from Update
 		virtual void update(Skeleton &skeleton, Physics physics) override = 0;
@@ -80,6 +78,10 @@ namespace spine {
 			return PosedGeneric<D, P, P>::getData();
 		}
 
+		virtual bool isSourceActive() override {
+			return true;
+		}
+
 	protected:
 		virtual void pose() override {
 			PosedGeneric<D, P, P>::pose();

spine-cpp/include/spine/Posed.h

@@ -44,7 +44,7 @@ namespace spine {
 
 		virtual void resetConstrained() = 0;
 
-		virtual bool isPoseEqualToApplied() const = 0;
+		virtual bool isPoseEqualToApplied() = 0;
 
 	protected:
 		virtual void setupPose() = 0;
@@ -115,7 +115,7 @@ namespace spine {
 			_applied = &_constrained;
 		}
 
-		virtual bool isPoseEqualToApplied() const override {
+		virtual bool isPoseEqualToApplied() override {
 			return _applied == &_pose;
 		}