Interactive mesh display in iJulia notebook

On my `feature/html` branch I've added a feature so that if you're using iJulia Notebook it will display a mesh in a little interactive window. This is really great for making changes to a mesh and seeing how the mesh is affected.

This builds on @jaakkor2's work with THREE.js export.

Demo [on my gh-pages branch](https://baconscript.github.io/Meshes.jl/).

[![Mesh display](http://imgur.com/Ad6Y69k.png)](https://baconscript.github.io/Meshes.jl/)