WIP
Merge branch 'develop' into comp-ui-refactor
Merge branch 'develop' into comp-ui-refactor
much better handling of learned components that don't actually load components
reject already known tag names, and some improved cutoff control
Merge pull request #870 from Pomax/comp-ui-refactor

reject already known tag names, and some improved cutoff control
Merge pull request #865 from mozilla-appmaker/comp-ui-refactor

Component UI resiliency in the face of broken components.