Socket.open() is a private API

Also see https://github.com/LearnBoost/engine.io-client/issues/175
fix: build engine.io.js dynamically for webworker test

This avoids the problem of testing against a stale engine.io.js file.
Merge pull request #240 from defunctzombie/fix/build-worker

fix: build engine.io.js dynamically for webworker test
update to has-cors 1.0.3

Fixes graceful fallback if XMLHttp request is disabled in IE
Merge pull request #241 from defunctzombie/fix/disabled-xml

update to has-cors 1.0.3
Merge pull request #234 from mokesmokes/patch-1

Socket.open() is a private API
fix captcha in comment
Merge pull request #242 from lzyzsd/master

fix captcha in comment