Showing / hiding others' public tags in viewed text

[tanius]

This would be implemented as part of the sidebar UI (see #50). The current proposal for how to implement it is about this:

• The main part of the sidebar would show a list of tags, with all own tags at the start and all public tags of others at the end of that list.
• In both parts of this tag list, tags that appear in the currently viewed content would come first and be somehow highlighted. The other parts of the list would attract less attention and ideally could be folded into a single line.
• Each tag entry in this list would have a checkbox to show or hide the corresponding annotations in viewed content. The selections made here would apply to any content visited until changed in the sidebar again.

That's it for this feature. However it's UI should be prepared to allow implementing other operations on tags later (for example, editing tag properties, forking, merging).

The tag list would be a flat list. That is a safe assumption, since it seems we do not need tag grouping or tag hierarchies in Open Ethnographer. If this is later added, we'd have to see if the sidebar interface should support operating on multiple tags based on such group / hierarchy relations or not. Could possibly be a second tab in the sidebar that only lists such aggregate elements and allows operations on them. Not sure about this part.