Add explicit path to testem in.
Add explicit path to testem in.

In case someone doesn't has nodemodules in the PATH

stefanpenner/ember-cpm,lolmaus/ember-cpm,ulisesrmzroche/ember-cpm,mike-north/ember-cpm,lolmaus/ember-cpm,stefanpenner/ember-cpm,ulisesrmzroche/ember-cpm,elwayman02/ember-cpm,elwayman02/ember-cpm,mike-north/ember-cpm,elwayman02/ember-cpm,mike-north/ember-cpm,lolmaus/ember-cpm,ulisesrmzroche/ember-cpm,stefanpenner/ember-cpm