option to display insertions/deletions inline

[dave-doty]

We want to support insertions/deletions as a first-class object directly.

However, sometimes the user may wish to view the design with each Strand appearing to be exactly its length. The main reason to use insertions/deletions is to be able to use a "normal" tick mark spacing (e.g., 8 bases for a flat origami on the square grid) to visualize "domains", while allowing some domains to be a different length. For example, twist correction in the square grid (see also here and here) involves making every 3rd or 4th domain length 7 instead of 8, using a deletion.

Instead, this could be visualized as simply shrinking the domain, i.e., not depicting the deletion, and in this example having only 7 bases between each major tick mark.

However, this would not be done by converting the design data, since we want to retain the insertion/deletion data. It should merely be an option for visualizing, but turning off the option should go back to displaying insertions/deletions as they were.