Fix Urdf loader for cases of absolute file paths for meshes

VirtualRobot/Import/URDF/SimoxURDFFactory.cpp

@@ -155,6 +155,12 @@ namespace VirtualRobot
 
     std::string SimoxURDFFactory::getFilename(const std::string& f, const string &basePath)
     {
+        if (f.find(basePath) == 0)
+        {
+            //f is already absolute
+            return f;
+        }
+
         std::string result = f;
 
         std::string part1 = result.substr(0, 10);