Added radioactive skill

This implementation of radioactive splits one-sided dice into a one-sider and a zero-sider. However, it is trivial to change this back to splitting into two one-siders if this is decided.

There is currently no game-level or interface-level test for radioactive, and this might be a *good thing* to have.  ;)

Also, I'd appreciate feedback on the action logging that I've included for attacker die splitting.

http://jenkins.buttonweavers.com:8080/job/buttonmen-blackshadowshade/491/
(and I'll fix the PMD warnings once I work out how to do so)
As far as I understand, some of these were put there during the initial creation of BMDie in anticipation of future development, and have never been used. I'd be fine with tidying these up under another issue.