Merge pull request #2 from oli-obk/master

agsxmpp now depends on a project outside its repository
Merge pull request #3 from oli-obk/master

some stuff agsxmpp didn't expose yet, but supported internally
Merge pull request #4 from oli-obk/master
Disable building GSSAPI support and WinCeApi on Mono
Respond with error stanza to unknown stanzas
Merge pull request #5 from oli-obk/fix/invalid_iq
cleanup stanza related error code
refactor IQ, Message and Presence Errors into a single base class
allow the client to prevent automatic service-unavailable messages

useful when invisible or when an unknown contact tries to probe whether the client is online
Merge pull request #6 from oli-obk/fix/error_response
prevent service-unavailable stanza sent in response to error stanzas
Merge pull request #7 from oli-obk/fix/service-unavailable-loop
add the encryption-required failure condition to the interface
add the possibility to force Tls (prevent login if tls is not present)
internal stanza handling was not recognized, causing service-unavailable messages on handled stanzas

the SaslHandler directly connected to the StreamParser to get its stanzas, while the service-unavailable stanzas are sent from the XmppClientConnection (which is also connected to the StreamParser)
the StreamParser's stanza event now checks whether the stanza was handled and otherwise raises an event (to which XmppClientConnection subscribes in order to send service-unavailable stanzas)
Merge pull request #9 from oli-obk/fix/service-unavailable
Merge pull request #11 from oli-obk/stable
Merge branch 'stable'

Conflicts:
	agsxmpp/agsxmpp.csproj
NullReferenceException happened when a server replied with an error to an auth info request

this usually happens when you connect to a server that requires encryption but you have not enabled tls
Merge pull request #12 from oli-obk/fix/nullref