Add the Lurch content dictionary editor to the OM Web site

[kohlhase]

@nathancarter showed us the Lurch OpenMath CD editor prototype at the OM Workshop, it should be integrated into the OM Web site.

[nathancarter]

I'm glad to help with this. In fact, one of the things I'd like to do in Fall 2017 is clean up the Lurch github repository significantly, including factoring out demo applications into their own projects. That might make it easier to integrate that editor into your site. I'm also glad to help create tutorials, etc. for it at that time, and add any features we all think would be useful.
The direct link to the application Michael is talking about is here:
https://nathancarter.github.io/weblurch/app/openmath-example.html