clean up time_poisson_interactive.py
clean up time_poisson_interactive.py

- rename gen_lines() -> gen_probes()
- show the last figure with --show option

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