add initial SDF importer, work-in-progress (still too incomplete to be useful)

examples/Importers/ImportURDFDemo/BulletUrdfImporter.h

@@ -4,6 +4,7 @@
 #include "URDFImporterInterface.h"
 
 
+///BulletURDFImporter can deal with URDF and (soon) SDF files
 class BulletURDFImporter : public URDFImporterInterface
 {
     
@@ -18,6 +19,11 @@ public:
 
 	virtual bool loadURDF(const char* fileName, bool forceFixedBase = false);
 
+    //warning: some quick test to load SDF: we 'activate' a model, so we can re-use URDF code path
+    virtual bool loadSDF(const char* fileName, bool forceFixedBase = false);
+    virtual int getNumModels() const;
+    virtual void activateModel(int modelIndex);
+    
 	const char* getPathPrefix();
 
 	void printTree(); //for debugging