uint128: Properly return values from operators, and fixed YAML I/O
Tests: Add extra debugging information to test_create_delete in test_dbserver
Tests: Fix add_channel in common.py.
Tests: Allow loglevel to be specified by environment var.
Tests: Fix expected remaining values in test_dbserver.
Tests: Improve log output for matches_header and one usage in TestStateserver.
128-bit: Use read_channel/add_channel/size_of(channel_t).
Used instead of uint64/8-bytes in a couple of cases
where it was missed previously.
MessageDirector: Check that participant != Null in error message to prevent segfaults.