Test entity validators

[jrjohnson]

Now that we have validators added to all the entities we should, as much as possible, test to ensure they are there. This will prevent accidentally removing them (since they are just comments) or track any breaking changes.

Example of some course validator testing:
https://github.com/ilios/ilios/blob/master/src/Ilios/CoreBundle/Tests/Entity/CourseTest.php#L25

[vpassapera]

http://www.slideshare.net/rdohms/annotations-in-php-they-exist-38513622

:)

[dartajax]

@jrjohnson can we close this pretty soon?

[jrjohnson]

I'm closing this generic ticket. We will want to add tests as time permits.