Implementation of Tizen SSO APIs

Implementation of SSO APIs as per widl file https://code.google.com/p/accounts-sso/source/browse/widl/signon.widl?repo=libgsignon-glib

Backend that provides core functionality is gSSO and more information about that
component could be found at https://01.org/gsso
No need to call `then()` as nothing to do for returned Promise.
I would prefer:`_destroyIdentity(identobj);`
Sorry missed this one in my previous review