Merge pull request #1 from cnnic/master

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Error response and variants table are modified.

1). The type of element "description" in Error response is changed from
string to string array;
2). One column named "idnTable" is added to table "variants".
Modified the response format of the Error and name server.

1). The type of element "description" in Error response is changed from
string to string array;
2). the format of IP address in the response of name server is changed
according to the newest draft.
Merge pull request #2 from dengguangqing/master

Error response and variants table are modified