HPCC-10680 Add Unicode support for Graph Control Messages

Fixes HPCC-10680

Signed-off-by: Gordon Smith <gordon.smith@lexisnexis.com>
Merge pull request #150 from GordonSmith/HPCC-10680_Unicode_Messages

HPCC-10680 Add Unicode support for Graph Control Messages

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>