give l-systems their own project page

I decided not to go with a git submodule here because I only needed the
web export file and that's ignored in the repo that generates it. if I
ever need to update it I only need to replace one file.
add l-systems n'at to the list of projects

I REALLY need to automate the building of this page so I don't have to
update the even/odd classes every time I add a new project description.