Allow an ignore list on constructing SpectrumDetectorMapping.

Enables filtering of given IDs when the list is first constructed.
Refs #7890
Fix spectrum numbering for ISIS event files.

Uses new ignore id feature on SpectrumDetectorMapping and also
sets the spectrum numbers on the resized EventWorkspace to those from
the file.
The default numbering scheme of starting at 1 is not sufficient as
a monitor block may be start of the table.
Refs #7890
Revert "Fix spectrum numbering for ISIS event files."

This reverts commit da7c0c809f4ad082b899fb0f461eefacceea6433.
Correct fix for the spectrum numbering in ISIS event files.

Refs #7890
Correction of SANS adding data

revert changes made in #7600 that was build over a bug in
loading event data.

re #7890
Merge remote-tracking branch 'origin/bugfix/7890_isis_event_monitors'