Initial commit of AAF SAML microservice

Commits base project structure for the AAF SAML microservice including:
    * Rails 4
    * [Sequel](http://sequel.jeremyevans.net/) instead of Active Record
    * RSpec3
    * Rubocop
    * Guard

Commit ensures all base project files pass Rubocop checks.
Don't use deprecated rubocop patterns
Enhance test configuration to support Sequel
Models SAML 2.0 Endpoint

See SAML Metadata specification for full detail on this model.
Models SAML 2.0 IndexedEndpoint

See SAML Metadata specification for full detail on this model.
Add all specific SAML 2.0 service endpoints

See SAML Metadata specification for full detail on these models. Inheritance is represented exactly per SAML specification.
Add initial readme
Merge branch 'master' of https://github.com/ausaccessfed/saml-service