Socket.open() is a private API

Also see https://github.com/LearnBoost/engine.io-client/issues/175
add xmlhttprequest to component.json

fixes #235
Merge pull request #236 from defunctzombie/fix/component

add xmlhttprequest to component.json
polling-xhr: fix ie10 webworker tests
websocket: document `ws` require
fix Makefile

actually depend on source files for build of engine.io.js
Merge pull request #238 from defunctzombie/fix/makefile

fix Makefile
fix GH-207
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
undo removal of onclose for websocket api compattibility
Merge pull request #234 from mokesmokes/patch-1

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

fix captcha in comment
Bumped zuul version to 1.5.2
Merge pull request #246 from gterrono/bump-zuul-version

Bumped zuul version to 1.5.2
Use !this.xhr for testing in cleanup method