#87 context menus for faster annotation

[Philip Ogren]

One mode of annotation creation that has been discussed is to have a context menu that appears immediately after text has been highlighted giving a list of classes/instances that when one is selected an annotation is created of that class/instance. This menu might contain a fixed set of types from the annotation schema which is changed through a configuration step. Alternatively, the menu could contain a set of most frequently/recently used types.

This would likely be implemented as a mode that can be turned on or off and provides one more way to speed up manual annotation creation.