Method from_file in class GridProperties should have functionality to autodetect property names

So far one has to supply the names to be read for grid properties in a file. This can quite easily be made more robust by autodetection of parameter names. The suggestion is to have an option for the names variable to be set to "autodetect". This will give the ability to read a file without any prior knowledge of the contents. This should not make the method much slower, just more robust.