Selenium updates

This PR contains the following updates.

* Update to latest selenium version (2.4.2)
* Update selenium download URL, as it has changed.  See [this note](https://code.google.com/p/selenium/downloads/detail?name=downloads_location&can=2&q=).
* Update readme example, since the 2.32.0 version used in previous example is not available at the new download location
* Bump version - Bumped minor rather than patch version as this is a potentially breaking change.  The new selenium download location only stores versions 2.39 and newer.

_NOTE:  This PR could be modified to support the old download location as well, if you feel there is value in keeping legacy support intact._