Driver can enable or disable PhantomJS cookies

As of 1.7, PhantomJS allows its `CookieJar` to be enabled or disabled using the
`cookiesEnabled` function. This commit adds access to that from the driver
using a similarly named `cookies_enabled=` method.

For more information on the API, check out:

https://github.com/ariya/phantomjs/wiki/API-Reference-phantom#cookiesenabled-boolean
Merge pull request #300 from mfrost/cookies_enabled

Driver can enable or disable PhantomJS cookies
Improve PhantomJS version checking

Naive implementation of raw string comparison fails on version
starting from '1.10.0'. The new implementation converts version parts
to integers and checks them in turn starting from major part.
Merge pull request #318 from hron/improve-phantomjs-version-checking

Improve PhantomJS version checking
Fix within_window finding window after close/open

Poltergeist was caching the page returned from getPage.  If a popup
window was opened and given a name, then closed, and a new one was
opened with the same name, we couldn't see it because we still had the
old page cached.

This change removes the cache and instead always asks phantomJS for the
page.

Fixes #312
Disallow breaking version 0.5.0 of faye-websocket

Their 0.5.0 release broke some APIs that Poltergeist uses. See #320.
Merge pull request #321 from turadg/patch-1

Disallow breaking version 0.5.0 of faye-websocket
bump version
Replace faye-websocket with websocket-driver.
Can set cookies for given domain
Merge pull request #306 from route/set_cookie_domain_option

Can set cookies for given domain
fix changelog
Merge pull request #313 from ryansch/fix-multiple-popups

Fix within_window finding window after close/open
fixup changelog [ci skip]
Tie 1.0.X to faye-websocket 0.4

Conflicts:
	README.md
	poltergeist.gemspec
Tie 1.1.X to faye-websocket 0.4

Conflicts:
	README.md
	poltergeist.gemspec
Migrate to websocket-driver 0.2.0, which handles HTTP parsing for us.
We no longer need http/parser
Fix process spawn pgroup error on Windows
Update changelog to note pgroup error fix