一些优化

优化 Date.prototype.format
修复题目分类解析错误的问题
Interface Tdoc
X-Forwarded-For 支持

hydro/error.ts

@@ -52,6 +52,7 @@ export const ForbiddenError = Err('ForbiddenError', UserFacingError, 'ForbiddenE
 export const NotFoundError = Err('NotFoundError', UserFacingError, 'NotFoundError', 404);
 export const MethodNotAllowedError = Err('MethodNotAllowedError', UserFacingError, 'MethodNotAllowedError', 405);
 export const RemoteOnlineJudgeError = Err('RemoteOnlineJudgeError', UserFacingError, 'RemoteOnlineJudgeError', 500);
+export const SendMailError = Err('SendMailError', UserFacingError, 'Failed to send mail to {0}.', 500);
 
 export const AlreadyVotedError = Err('AlreadyVotedError', ForbiddenError, "You've already voted.");
 export const LoginError = Err('LoginError', ForbiddenError, 'Invalid password for user {0}.');
@@ -103,6 +104,7 @@ global.Hydro.error = {
     BlacklistedError,
     ForbiddenError,
     NotFoundError,
+    SendMailError,
     LoginError,
     CsrfTokenError,
     MethodNotAllowedError,
@@ -188,9 +190,4 @@ class InvalidArgumentError(BadRequestError):
   @property
   def message(self):
     return 'Argument {0} is invalid.'
-
-class SendMailError(UserFacingError):
-  @property
-  def message(self):
-    return 'Failed to send mail to {0}.'
 */