Graduate Brain Slug

If you're graduating, doesn't your brain slug deserve at least some of the credit?

Here's a heavily tweaked version of [Brain Slug V2](https://www.thingiverse.com/thing:33325) that has the following improvements:

* Separate-print graduation cap (mortar board), complete with antennae holes and hole and cavity for mounting a tassel
* Separate-print eye, which can easily be printed with the eyeball in black by changing filament at the appropriate layer -- and you can use different filament,