Merge remote branch 'origin/feature/9390_convert_empty_to_tof'
Package up the html help

Use the same location that the QtAssistant helpused to go.
Refs #9611
Switch from qtassistant to web browser ...

pointing at a local copy of the documentation.
Refs #9611
Remove qtassistant and wiki tools

No longer required now that the documentation is in the rst files.
Refs #9611
Fix broken category links.

Refs #9611
Use cmake variable to control packaging of offline documentation

It's not built by all platforms on incremental builds so it needs to be
turned off in these situations.
Refs #9611
Merge branch 'feature/9611_package_html_help' into develop