Invalidate or signout

Invalidate accessToken using accessToken and clientToken:

boolean invalidate = MojangAuth.invalidate("access token", "client token"); // true if succeed

Invalidate accessToken using login and password:

boolean signout = MojangAuth.signout("example@example.com", "password"); // true if succeed

Analogs: https://authserver.mojang.com/invalidate, https://authserver.mojang.com/signout