This features didn't work well, had a lot of artifacts and generally
wasn't very useful. This kind of effect should be accomplished
differently.
This is an API break because BloomOptions::anamorphism has been removed.
This updates the tutorial markdown, fixes up the literate programming
Python script, and updates the web site itself.
The doc build script now uses a Pipfile instead of "requirements.txt",
which I find less frustrating since it does not interfere with other
Python projects on your machine.
Fixes#2483.
