Swap current ExecutionEngine to use MCJIT.
Brings support for exceptions and inline assembly among others.
ROOT 6 on PPC64
ROOT 6 cannot handle exceptions in invoked functions
ifstream does not work properly in cling on MacOS 10.9
can not throw exception through ROOT/meta wrappers
Cling cannot handle assembler (e.g boost::shared_ptr)
Asynchronous operations at the prompt: thread works, async does not
crash using cout on MacOS 10.9 - inline asm?