Added the ability to use UPal with D7.

[jordansebastian]

I added a new environment variable to phpunit.xml.dist that indicates which version
of drupal core you intend to use. This is then loaded in drupal_test_case.php and
used to determine how to find bootstrap.inc.

[weitzman]

Thanks! I'll have to look into this a bit more - will comment here. Do you have tests running with Drupal 7 now? I'd like to know the full scope of the changes that are needed before I commit to supporting two major versions of Drupal.

I noticed that there are changes to phpunit.xml.dist. You will want to copy the contents of that file to phpunit.xml and revert the .dist file so that you don't accidentally put your password in a pull request :)

[jordansebastian]

Reverted the phpunit.xml.dist file, but kept the new environment variable that lets you switch between 7 and 8. I'm going to run more tests against core for now and report back.

[jordansebastian]

The latest commit fixes a few problems I was running into. I'm continuing to test core modules and things seem to be going well. I'll put a list of them here soon.