To mass import accounts, simply create a text file with each account details on a separate line. The format to import accounts can be either of 3 things:
With each format you can also add optional cookies. To do this simply add "::" after your account details and then type "cookie_name:cookie_value". If you want to add multiple cookies, just separate them with "|".
An example of an account being imported with cookies:
After this has been done, right-click anywhere on the account overview then click on New Account > Import File. A dialog will pop-up, asking you what file you want to import, simply select the file you created.