Don't pollute the global Object namespace

:see_no_evil: Remove the monkeypatch on Object so we don't polluate the global Object namespace
:twisted_rightwards_arrows: Renames `uses` to far less generic `spec_uses` to avoid conflicts with any  `uses` method in code that uses SpecRequirer
:twisted_rightwards_arrows: Also renames `uses_models` etc. to `spec_uses_models` for consistency
:memo: Configuration is now slightly different, README is updated to reflect the need to `include SpecRequirer` as well as calling `.setup`

I've tested this with HouseBot and it appears to work well.