Allow expected exception without needing to setup a callback

Ideally I would provide a test case which I expect to fail, but not sure of how to do that with pecs.
Tweaking whitespace

My editor managed to screw things up, this is sorted it out.
Alias should to it

So we don't have to sprinkle our tests with "should" noise.
E.g. should('catch an expected exception')
Remove pecs namespace from internal function calls