Engine-XMPP: wasn't able to close unsynced (not fully joined) mucs

in case of long delays this could easily happen
also, regression-danger due to nonexisting chat windows that the server might send messages for
Engine-XMPP: a server<->client race condition could cause a closed chat to be joined

now this kind of chat is automatically closed and an error message is displayed in the protocol chat
this required a refactoring of OnGroupChatPresenceError because that function expected a non-null XmppGroupChatModel
Frontend-GNOME: fixed leaking PersonTags in MessageTextView (refs: #667)
Merge branch 'stable'
Engine(-Tests): fixed matching git+ssh:// URLs
Engine(-Tests): fixed matching URLs that contain a ! in the path
lib/Twitterizer: updated to fix enforced HTTPS as of 14 Jan 2014 (closes: #940)
lib/Twitterizer: updated to fix enforced HTTPS as of 14 Jan 2014 (closes: #940) (smuxi-master)
Engine-XMPP: could not connect to xmpp due to ProtocolManagerInfo name clash with jabber
Merge pull request #170 from oli-obk/fix/xmpp_jabber_name_confusion
Engine-XMPP: got serialization exceptions due to sending XmppPersonModels
Merge pull request #171 from oli-obk/fix/serialization_exception_xmpppersonmodel
Engine: don't match final ! in URLs
Engine: fixed matching URLs containing @
Engine(-Tests): fixed matching URLs containing :
Engine: fixed matching ports 1-9 in URLs
Engine: support and link RFC section and pages
Build: avoid unneeded WCF assembly references for ServiceStack.Common
Engine(-Tests): don't match upper-case letters in domain and TLD for heuristic links

E.g. ServiceStack.Common FSharp.Compiler
Engine-Tests: cover RFC smart link