new interactive example with time stepping

Hi,

I have just updated the time stepping solvers in sfepy for interactive use, as demonstrated in the new example [1]. For basic use, ignore the probing code - the time stepper can be used as simply as:

tss = SimpleTimeSteppingSolver({'t0' : 0.0, 't1' : 100.0, 'n_step' : 11}, problem=problem) tss.init_time() for step, time, state in tss(): pass

r.

[1] http://sfepy.org/doc-devel/examples/diffusion/time_poisson_interactive.html