[services] add Set the CamaraFP far clip

Following mail from Jan-Erik Platte on morse-users.

http://www.blender.org/documentation/blender_python_api_2_69_1/bge.types.KX_Camera.html#bge.types.KX_Camera.projection_matrix

While here, fix get_structured_children_of, get_obj_by_name methods.