Using TestTrait instead of BaseTestCase.

Because @before and @after are only supported with traits in PHPUnit now, not for super classes
Removing Eris\BaseTestCase, can only cause problem since when used @after and @before do not work
Accepting a seed as an environment variable and dumping it at the end of the test
Printing a command for reproducing only for red tests
Merge branch 'supporting_seed'

Conflicts:
	examples/SumTest.php