widget: Emit title-changed and uri-changed only if the value really changed
widget: Emit title-changed and uri-changed only if the value really changed

https://bugzilla.gnome.org/show_bug.cgi?id=782863
(cherry picked from commit 9bc33bdd967887db026f5267ae7db28e6bfcfeef)

thestinger/vte-ng,thestinger/vte-ng,thestinger/vte-ng