Altered code to properly handle asymmetric twin swing dice

Fixes #1467.

http://jenkins.buttonweavers.com:8080/job/buttonmen-blackshadowshade/555/
The complete solution for die types being passed to the API would probably require me to make a parallel flagging system for types. It wouldn't be difficult, since I could subclass BMFlagProperty and BMFlagType from BMFlag, but it would require touching a lot of BMFlag files and changing how the API interprets BMFlags.

I would suggest moving this to another issue.