Making sure that when the MPI parcelport is used only the ranks are compared
Fixing communication between MIC and Host

 - The intel compiler on the host didn't have the right HPX_GCC_VERSION thus the correct is_bitwise_serializable specialization wasn't picked up.
 - Modified tuple serialization to respect if no array optimization should be used
 - Added code to allow array optimization for single elements
Added HPX_NATIVE_MIC preprocessor define if it was set during cmake configuration.

Modified hello world message to print if it was ran on a Xeon Phi
Making this compile with Intel MPI again