Used registry to hide fields on a class
Filter out hidden fields from AR view
Added filtering of hidden attributes on AR table view
Added hiiden attribute filter to Sample view
Hide hidden attrib on AR Invoice view (create isAttributeHidden util method)
Extra checks for SamplePoint in add.py
Changed except/pass to raise runtimeerror
Remove prints and comments
Added optional attributes robot test
Hide Results Per Sample Point report if sample point is hidden
Added hiddea nattributes filter to worksheet analyses listing
Minor refactor of hidden attributes filter on ARs
Merge branch 'alspec-s2.1' into alspec-int

Conflicts:
	bika/lims/browser/analysisrequest/__init__.py
Fixed merge mistake - removed AnalysisRequestsView from __init__.py
Merge problem - moved hiddenattributes functionality from __init__
Run plone.app.registry upgrade step
Upped metadata version
Secure hiddenattributes look method - esp check if empty registry
Merge branch 'develop' into alspec-int
Cleanup

Demote runtimeerror to warning

WidgetVisibility checks are done at the point where the adapter is
used, not in the adapter itself.  This means that subclassed adapters
don't need to worry about this stuff.

review_states modified centrally in bika_listing.  This means that
subclassed bika_listing/folderitems does not need to worry about this.
Merge pull request #1234 from bikalabs/alspec-int

Alspec 2 integrarion

It's not a complete solution, and many areas do not respect these settings.