move adapter out
Readme: document `Socket#emit`
Readme: document `Socket#to` and `Socket#in`
Readme: document `to` multiple-call situation
Readme: document `Socket#join` and `Socket#leave`
Readme; document `Socket#id`
socket: fix `flags` `api` state
style
added support for volatile packets
server: make `Server#adapter` work after construction
bump client
bump engine.io
package: bump `engine.io`
Merge remote-tracking branch 'upstream/master'

Conflicts:
	lib/adapter.js
	lib/namespace.js