fix caret display in tables and before/after pseudo elements for tables

The anonymous table boxes are not associated to a node, so getContent()
returned false and those boxes where not considered for caret placement.
This commit also adds before/after pseudo elements to a table.

Change-Id: I4376fef23bc7990e11cf0765cdc6465c462f2d3d
Signed-off-by: Carsten Hiesserich <carsten.hie@gmail.com>
4 files changed