[AESinks] Fix things found by Cppcheck

Inspired by @kylhill and curios what can be found with a free tool, I check the sinks with Cppcheck (http://cppcheck.sourceforge.net/).

Commits marked with [*REVIEW*] should be looked more closely by the corresponding dev.

I have not changed warnings like " Member variable 'CAESinkDirectSound::m_running' is not initialized in the constructor., because I don't know if these are considerable. The report of these can be found here: https://gist.github.com/ace20022/b7556b9640563efc9a32