Separrate Error Check from Set Columns in Slave PB

Future child devices need the ability to change the error checking
criteria while also invoking the parent (from Devices) method Set Columns.
This cannot be done unless the error check can be overriden separately
from the rest of Set Columns.  Thus Error Check Columns now does all error
checking and is called from within Set Columns.  Children can override
Error Check Columns to change error criterion.