update to tls >= 1.1.3
pontarius-xmpp.cabal: Bumb version number for new version on Hackage
pontarius-xmpp.cabal: Add other version updates (duh!)
dns 1.0 support
network 2.3.1.0 support
Merge pull request #42 from snoyberg/master

Add dns 1.0 and network 2.3.1.0 support
pontarius-xmpp.cabal: Bumb version number for new version on Hackage
make stanza handler plugins more flexible

stanza handlers used to return a Boolean value to indicate whether stanza processing should continue. Now the return lists of stanzas instead. This facilitates plugins that transform stranzas (e.g. encryption)
export writeStanza
export all modules for easier reuse
correct some documentation errors
add plugin interface
improve, document and export lenses
more lenses
add messagS and presenceS stanza template
yet more lenses
improve plugin interface

Plugins will now be handed the xmpp session once it is created so they can tie the knot if necessary
more work on lenses

rename stanza classes
add traversable for payload
change sid lens to point to Maybe Text
export pluginsL
add lenses for instant messages
add remaining lenses for roster types