allow open and close reigsters
merge upstream
add vend machine config for switching between basic auth and oauth
tweak store initialize, taking credential hash instead
update store spec for oauth support
update Readme.md to handle Ouath support
remove dev test helper method
Add invalid config error
Update Vend Config

- Remove unnecessary attr_accessor
- Remove reset method and self.reset call
- Tweak auth_method setter
- Tweak auth_method getter and default to basic_auth
Fix Typos
Merge pull request #3 from alex-zige/master

Add Oauth Support