Visualization of the standalone ComponentDefinitions

[cjmyers]

DNA glyphs should be able to be added to the Canvas not on a backbone and visualized as their role for the corresponding CD. Similarly, if a Module with FC that are CDs with no components is opened, these should be visualized as standalone glyphs without a backbone.

[cjmyers]

See also #197

[cjmyers]

I'm not sure this exactly working. The solution you pushed is actually solving a slightly different problem.