Happy Thanksgiving! Here's SDR 0.7 to celebrate the holiday. Version 0.7 incorporates a number of dance engine refactorings completed shortly after the previous release promised them, as well as (more recently) a number of new call and concept definitions (and test cases) inspired by the C4 calls I am currently studying. I also updated Google App Engine and Google Web Toolkit to the latest versions for the web app, although jMonkeyEngine is still stuck at 2.0 — we might get an Android version of SDR if I manage to rebase to jMonkeyEngine 3.0 for the next release.
Breathing the square properly is still a challenge. Other square dance programs only treat starting and ending formations, but SDR has to consider all of the intermediate positions along the dancers' paths. This leads to some very unusual formations being breathed. As mentioned in the notes for the last release, SDR formulates breathing as a solution to a mixed integer linear programming problem—but there are still a few bugs lurking which cause the constraint solver to blow up from time to time (especially from columns, for some reason). Hopefully I'll be able to dig into this for the next release.