OpenForge 2.0 Magic Circle: Blanks

I got a request for blank pieces so that other people could make their own magic circles. These are blanks for a stand alone circle, 2x2 cut stone circle floor and 4x4 cut stone circle floor.

For instructions on how to get started with OpenForge, we have a set of [tutorials](https://github.com/devonjones/openforge-tutorials/blob/master/README.md). Want to sell OpenForge prints? Want to use OpenForge designs in your product, check out the [license](https://github.com/devonjones/openforge-tut