Fix for token id_token combination as per oauth-v2-multiple-response-types-1_0

Section 5 from http://openid.net/specs/oauth-v2-multiple-response-types-1_0.html#Combinations lists the valid combination as id_token token.  After this change both the sample request from the same section and the sample request from http://openid.net/specs/openid-connect-core-1_0.html#id_token-tokenExample are treated as valid.