Filter our zero-coverage updateState nodes
Filter our zero-coverage updateState nodes

Added filter for nodes being passed to update state event - this
ensures that nodes are not being included with zero-length coverage, a
side effect of how selectNodes handles the virtual boundaries of text
nodes.

Change-Id: I6362114b57469b1108da11f94dc345a2bcdfc7cd

wikimedia/oojs-ui,wikimedia/oojs-ui,wikimedia/oojs-ui,wikimedia/oojs-ui