Add of distributed algorithm for the reference table creation in abc model choice. Documentation for abc model choice methods.

change the stop criteration of a ContinuousTimeModel simulation.
Minor fix  in ContinuousTimeModel for the euclidean distance automata
tests.
Add of a test for stop criteria simulation of ContinousTimeModel
(unit/simulation_stop_criteria).

All tests passed.

Fix of distributed abc smc tests + add of a test.
Preparation for the new feature: add a stop criteria in the simulation.
All tests passed.