Improve Gemspec.

* Autoload bin and lib directories.
* Version dependencies.
* Reference license.
* Add description.
Update Gemfile.

* Reference RubyGems correctly.
* Add pry for debugging.
Fix service overwrite rule.

Since it is set to the default service on #initialize, the #set_service
method never takes.

https://github.com/joeworkman/paperless/blob/master/lib/paperless/engine.rb#L86
Remove Bundler.require cruft.
Merge pull request #10 from unsay/fix_service_overwrite_rule

Fix service overwrite rule