update GmshIO.read_data() to work with postproc.py
update GmshIO.read_data() to work with postproc.py

rc/sfepy,vlukes/sfepy,BubuLK/sfepy,rc/sfepy,BubuLK/sfepy,sfepy/sfepy,vlukes/sfepy,sfepy/sfepy,sfepy/sfepy,rc/sfepy,BubuLK/sfepy,vlukes/sfepy