Merge pull request #12 from disabler/master

client-side captcha, disco#items, iq-ping  — all by @diSabler
Merge branch 'master' of https://github.com/mrDoctorWho/vk4xmpp
* some code cleanup in gateway
* parts of code deleted or moved into modules
* now transport should not write null exceptions
! update may cause errors, revision didn't tested well
add: more statistic by stats request
add: registration watcher