Forward the SELENIUM_BROWSER environment variable into the Vagrant VM

Trying out a new way of running Selenium tests that seems to work better.
Rather than going through the `selenium` management command,
I'm running the `test` command directly and passing in a test pattern of
`uitest*.py`.

This seems to work better with the Jenkins Sauce Labs plugin.
Install Sauce Connect inside the Vagrant VM

This appears to be a more stable way to connect to Sauce Labs, and
should allow for easier parallelization of UI tests
Autocorrect Vagrant ports when in the TEST environment

Should allow for easy parallelization of UI tests
Make use of Sauce Connect role to install Sauce Connect