schroedinger.py: use ensure_path(), allow only one of --mesh, --create-mesh
schroedinger.py: use ensure_path(), allow only one of --mesh, --create-mesh

sfepy/sfepy,rc/sfepy,RexFuzzle/sfepy,sfepy/sfepy,rc/sfepy,BubuLK/sfepy,RexFuzzle/sfepy,BubuLK/sfepy,lokik/sfepy,vlukes/sfepy,RexFuzzle/sfepy,lokik/sfepy,lokik/sfepy,BubuLK/sfepy,RexFuzzle/sfepy,vlukes/sfepy,sfepy/sfepy,rc/sfepy,vlukes/sfepy,lokik/sfepy