Add missing tutorials for diffusion models #273

ChudleyElliottJumpDiffusion (#246) and JumpTranslationalDiffusion are missing tutorials

To do:

• Expand on existing diffusion tutorial by adding ChudleyElliottJumpDiffusion and JumpTranslationalDiffusion.
• Add a See also the tutorials. remark at the bottom of the class docstrings.
• Remove the TODO in chudley_elliott_jump_diffusion.py that points to this issue.

Raised in review of #246.