Update dumpfile
Various changes to update the dumping of measurements to file:
- Change
PMT::Mark
interface, replacingconst char *name
andunsigned tag
byconst std::string& message
- Remove the unused
first
state argument inPMT::Dump
- Make
PMT::Mark
virtual so that backends likePowerSensor3
can override it - Cleanup some variable names in
PMT::StartThread