update Problem for Variables replacing State
update Problem for Variables replacing State

- initialize ics in .__init__(), .create_subproblem(), .set_equations()
- remove .setup_ics()
- update .create_state() to call .get_initial_state()
- update .save_state(), .save_ebc(), .get_tss_functions(),
  .get_initial_state(), .solve(), .block_solve(), .save_restart(),
  .load_restart()

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