more specific token search for Collada Loader

collada can appear in many files, such as glTFs via the “generator” field (in the form of collada2gltf)

code/ColladaLoader.cpp

@@ -119,7 +119,7 @@ bool ColladaLoader::CanRead( const std::string& pFile, IOSystem* pIOHandler, boo
          *  might be NULL and it's our duty to return true here.
          */
         if (!pIOHandler)return true;
-        const char* tokens[] = {"collada"};
+        const char* tokens[] = {"<collada"};
         return SearchFileHeaderForToken(pIOHandler,pFile,tokens,1);
     }
     return false;