Glyphs for genes and clusters

[Jacob Beal]

Hi, folks:

There has recently been an issue raised about how to represent genes and gene clusters. Currently, people often reuse the "CDS" glyph, but that is not really correct, since these regions often include multiple distinct coding sequences.  It seems like we can solve this either by:

 - Adding new glyphs, or

 - Generalizing the semantics for the current glyphs

Please contribute to the discussion at: https://github.com/SynBioDex/SBOL-visual/issues/113

If we have a fast consensus, this might be able to be included in the SBOL 2.3 release

Thanks,

-Jake