Whitespace removal
Add required ruby version to gemspec
Whitespace removal
Refactors Frenetic configuration internals

* Remove Configuration object and replaces with going all in with
  ActiveSupport::Configurable

* Remove sticky Frenetic User-Agent headers. More trouble than its
  worth maintaining

* Add ability to reconfigure a Frenetic connection instance that has
  already been used.

* Move some mixins out of the "concerns" folder because the project
  organization got confusing

* Improve ConfigError message
Fix filename typo