Get the generator code directly to the foreman_api bindings

Generating the bindings is now provided directly through this repo.
Calling `bin/generate.rb` contacts the Foreman instance to get the
latest docs and generated the bindings from that source.
Regenerate bindings with the new generator
Remove the apipie dependency

Not needed anymore
Edit generator dependencies
Bump version
Update readme
Update the gemspec

Remove the apipie dependency and don't include the generator into the gem
Merge pull request #5 from iNecas/generator

Separate generator from the Apipie