Particle filter inference with changepoint model

[dominikglandorf]

This adds a trial generation and particle filter inference demo to the tests. Currently, the :event in th time step t-1 can be redrawn in rejuvenation (i.e. the event-associated latents)

Inference time analysis:
10 time steps completed (last step was 0.33 seconds)
20 time steps completed (last step was 1.30 seconds)
30 time steps completed (last step was 1.22 seconds)
40 time steps completed (last step was 1.41 seconds)
50 time steps completed (last step was 3.38 seconds)
60 time steps completed (last step was 4.14 seconds)
70 time steps completed (last step was 4.45 seconds)
80 time steps completed (last step was 5.21 seconds)
90 time steps completed (last step was 2.98 seconds)
100 time steps completed (last step was 3.41 seconds)

Results: