XMLHttpRequest using Chrome sockets

This is a XMLHttpRequest class using chrome.sockets.tcp on Chrome browser.

Forked from https://github.com/codeinchaos/chrome.sockets.tcp.xhr.

Please check documents from http://chromesocketstcpxhr.readthedocs.org/en/latest/.

Enhancements

• Get full response data, instead of only getting first segument data.
• Add content length checking from response header.
• Support only get HTTP 304 redirect URL.
• Support first received data timeout.