Improvement of sampler descriptions. (wip)

[trappmartin]

Here are some suggestions for improved descriptions of the samplers in Turing. Those are meant for the page: http://turing.ml/docs/sampler-viz/

• Change page to Turing Samplers
• Remove the code explaining how you get the picture and simply explain the model in the webpage.
• Use animations.

(wip: further improvement suggestions will follow)

cc: @cpfiffer

[trappmartin]

Gibbs

Turing's Gibbs sampler allows to combine samplers within Gibbs. As illustrated, the resulting sampler will construct axis aligned samples by drawing from each sampler within Gibbs. It is therefore preferable to sample many parameters jointly with a single sampler and distribute parameters only to few samplers within Gibbs.