Feature/omniauthhelper rehash

- Fixed #20 by rewriting OmniAuthHashHelper and OmniAuthHelper into `lib/login/omni_auth_hash_manager/validator.rb` and `mapper.rb`
- Full coverage for this new strategy
- Rewrote old tests to work in new strategy
`attr_reader :omniauth_hash_map`

    def omniauth_hash_map=(omniauth_hash_map)
       raise ArgumentError unless omniauth_hash_map.is_a? Login::OmniAuthHash::Mapper
       @omniauth_hash_map=omniauth_hash_map
    end