Update Firediff to ignore event that occur prior to content loaded and firebug objects.
Update Firediff to ignore event that occur prior to content loaded and firebug objects.

git-svn-id: 1eea4772218f19b46d0001e8386d39ee6738a9f6@5500 e969d3be-0e28-0410-a27f-dd5c76401a8b

kpdecker/firediff