Fix about methods of SynchronizedTrajectory + tests.

Simulation for ParametricModel works.

efficient.

First bricks of the automaton_abc algorithm.

Add several convenient methods for parameters of model.

Next step: implementation of simulate with resize!.

order to replace vcat by push!.

The benchmarks are at least equal, and better when the buffer size is
small. However, no significative difference of performance with adequate
buffer size.

My opinion the gain can be seen when simulations are going to be very
long with more complicated models than we have implemented for now.

All tests passed.

Add of a new type of Trajectory: SynchronizedTrajectory which is created
by the simulation of a synchronized model with an LHA.

Simulate function for SynchronizedModel executes and is tested by two
simple models.

Next step : Cosmos based tests.

Add of several useful functions for access values of model, lha and
trajectory objects.

an object.

Type stability of simulate, dist, read_trajectory seems to be preserved.