Ortho ported to Blender 2.80

The fourth add-on in my portfolio to be ported to Blender 2.80 is Ortho.

This add-on relies quite heavily on OpenGL graphics and was therefore a bit more challenging. Be prepared for all sorts of issues including crashes as long as Blender 2.80 is in beta (although to be honest, the beta has proven to be pretty stable already)