allow quadratic elements in ANSYSCDBMeshIO.read(), strip extra nodes
allow quadratic elements in ANSYSCDBMeshIO.read(), strip extra nodes

- allow more format variants
- add remap argument to mesh_from_groups()
- add .dat suffix

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