Fix message ref-counting in cyAvatar::RunBehavior

This was potential memory leak AND crash bug, all in one nasty package. I
included a little bit of code cleanup free-of-charge.
Fix invalid sizeof expressions in HeadSpin.cpp
Merge pull request #428 from Hoikas/cov

Trickle of Coverity
Add an hsDeprecated macro for declaring APIs deprecated
Put compiler checks in their own cmake module