Upgrade to latest Rspec.

With Rspec 3 now in the works, lets make sure we're up to date!

* Replace deprecated `stub` and `mock` with `double`
Update VCR cassettes w/latest BreweryDB.com changes

It's been a while since we recorded these, so lets capture some new
recordings and update things.
Add spec for including status code in error msg.
Convert to moder Rspec `expect` syntax
Use named subjects rather than abuse implicit ones
Use known key for precomputed nonce and key

Else setting a different API key, for examply, one that is paid for, to
allow us to get more results/access pro features, will cause this test
to fail. CONFUSING!
Update VCR Cassettes w/a Premium API Key

So we get full access to the API.