Add support for multithreaded libevent programs.
Add support for multithreaded libevent programs.

Change-Id: I10e438856c752c29a5f7991705a080f7649af520

aldebaran/libqi,bsautron/libqi,aldebaran/libqi-java,aldebaran/libqi,aldebaran/libqi,vbarbaresi/libqi,aldebaran/libqi-java,aldebaran/libqi-java