Allow writing hspec tests against Hoogle library

This patch begins the creation of hspec-based tests against Hoogle as a library, since that is the mode of usage we depend on most, and this will ensure that features we add in future do not break current functionality we depend on.

The only questionable aspect of this patch is the nature of the changes I had to make to hoogle.cabal, which now moves to a dependency on at least cabal 1.10.