This Is to address the comments on review board Here
PrinterState AXIS and MeasuramentUnits enums inside AtCore (or make them C++11 "enum class").
All enums are now members of AtCore
Also note how PrinterState AXIS MeasuramentUnits is not consistent naming
I have renamed them to AtCore::STATES AtCore:AXIES and AtCore::UNITS to have a consistent naming scheme.