script/convert_mesh.py: update --remesh option, improve help
script/convert_mesh.py: update --remesh option, improve help

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