Faster specs

Improve the tests speed by:

- preventing the specs from using ohai (there is still one test case that uses it, because it's an integration test - hence the 3 seconds still...);
- removing unnecessary requires.

Previously:

    Finished in 40.01 seconds
    35 examples, 0 failures

Now:

    Finished in 3.4 seconds
    35 examples, 0 failures

I have also included minor corrections to method descriptions and ruby 1.9 syntax.