Refs #8783 quick now cleans up

Quick and convert_to_wavelength were creating workspaces that weren't prefixed by an _

Quick was never calling cleanup because of a logical check which always evaluated to false under normal use
Refs #8783 Polarisation correction temp ws cleanup

I'd missed some workspaces used when performing polarisation corrections
Refs #8783 Merge remote-tracking branch 'origin' into feature/8783

Conflicts:
	Code/Mantid/scripts/Reflectometry/isis_reflectometry/convert_to_wavelength.py
Merge remote-tracking branch 'origin/feature/8783_quick_cleanup'