Fixes for DataQualityDict.from_veto_definer_file
This PR fixes a few problems with parsing and operating on veto definer files via the DataQualityDict
object.
Most of the changes are to enable handling infinities in the query methods, by default a veto_definer
entry may have an end_time
of 0 meaning 'endless definition', but the segment logic will always reverse that, which is a bit annoying.