add usage examples to quantum_common.py example
add usage examples to quantum_common.py example

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