Icon to toggle visibility of menubar

In an effort to simplify the world outline environment, I added codt that makes the menubar visibility toggle.

Click the blue wedge in the upper left corner of the screen to make it go away. Cick again to bring it back.

I'm probably going to switch this around to default the other way, but I wanted it to work this way so I could demo it for others who use Bootstrap Toolkit.

Perhaps this is a feature others want to impmement? Just View Source.

Also, I'm not the best icon guy or CSS guy, so if you come up with something you think is better, please let me know.

I wrote a blog post about this feature.

Parts