add missing tests for common test command invocations
test for test command aborting on invalid namespace

move abort-msg to helper and ensure it only catches main/abort
allow `lein test` to take file args

closes #996
remove failing report test that is no longer valid

removed at dfb951f430eb360d7f17128258968289d160381e
Merge pull request #1000 from cldwalker/test-command-takes-files

Test command takes file arguments