migrate tutorial "Using Salome with SfePy" (#171),  update MED file support

* update MED file support, fix this issue: https://groups.google.com/forum/#!msg/sfepy-devel/z1e83Xgl1_U/884jDfKzKPsJ

* migrate tutorial "Using Salome with SfePy" from google site

For discussion: where to place "Tutorials" like Using Salome, Primer, ...