Merge pull request #3 from alexhancock/master

Add a missing line of documentation
IE9 does not work with xmlNode.textContent
using Stophe.getText(xmlNode)
Merge pull request #4 from dimalev/rpc-IE9

IE9 does not work with xmlNode.textContent
Nickname support to the presence subscription request.

See http://xmpp.org/extensions/xep-0172.html#subscription
Merge pull request #5 from jcbrand/master

roster plugin: Nickname support added to the presence subscription request.
[plugins] Adds a plugin for sending custom HTTP headers over a Strophe.Connection