Enabled to treat veto pulses. Refs #8222.

1. Enabled to unmask event indexes with veto flag.
(unmaskVetoEventIndex)

2. Clean the codes

3. Fixed a bug to set the ordering flag of event lists.
Removed some disabled codes. Refs #8222.
Changed output workspace class type. Refs #8222.
Lowered the confidence for using version 2. Refs #8222.
Merge remote branch 'origin/feature/8222_preNexus_veto'