improve URL regex
When I turn RST off, and send a message like:
Gajim site <http://www.gajim.org/>`_ `
the >`_ part is included in the URL as seen in my chat window, which is a minor nuisance for clicking the link later on.
When I send it to another account on the same gajim instance, the same defect happens on both sending and receiving chat tab.
When I send it from Pidgin to gajim, the URL is delimited by the >.