[BUG FIXES]
- Updated die handler in MCE::Core::Worker and MCE::Signal (RT#102802)
Bug reported by Dmitry Karasik.
[ENHANCEMENTS]
MCE child processes call CORE::exit during exiting; previously CORE::kill.
Improved IPC stability on Windows and Cygwin.
Multiple calls to mutex->lock by the same process or thread is now safe.
The mutex will remain locked until mutex->unlock is called.