Hammer CLI

I think that we can drop the line from gemspec now. It's there from historical reasons when we needed to add upper limit to pin rest-client down to a ruby 1.8 supported version without releasing new apipie-bindings.

As apipie-params specifies '< 1.8.0', but 1.7.x already has verify_ssl on by default this would trigger unexpected behaviour from the user's point of view, so let's wait for apipie-params to get everything sorted out and remove the direct dependency then.