0.3 to 0.4

Major changes

• Added Lenses
• Added Plugins

newly exported functions

• simpleAuth
• jid (QuasiQuoter)
• presenceUnsubscribed
• associatedErrorType
• mkStanzaError

major bugs fixed

• Didn't check jid of IQResults

incompatible changes

IQ

• sendIQ returns an STM action rather than a TMVar
• sendIQ' takes a timeout parameter
• removed IQResponseTimeout from IQResponse data type
• renamed listenIQChan to listenIQ and changed return type from TChan to STM
• renamed dropIQChan to unlistenIQ