title: Remove login tokens for meteor auth
body: <p>I am not sure if this has been asked before but the <code>loginTokens</code> are getting really large and without any cleanup make my database increase in size. What is being done about this? what are others doing to manage this. I am referring to the default <code>Meteor.users.services</code> which has an array of loginTokens that get created every time the user logs in/out</p>
  
  <pre><code>"resume" : {
          "loginTokens" : [
              {
                  "token" : "HMntXepqzPBLDGkGX",
                  "when" : 1372559065392
              },
              {
                  "token" : "uCHqA95HZZyN5tRtH",
                  "when" : 1372563545565
              },
              {
                  "token" : "sNGZhhATTrTg8582w",
                  "when" : 1372622561176
              },
              {
                  "token" : "hPWpm4uQQXWrkK6NS",
                  "when" : 1372634411432
              },
              {
                  "token" : "DFntTEcsKKT6bJ3rx",
                  "when" : 1372635411745
              },
              {
                  "token" : "BBM3acLQhuNtsHvkn",
                  "when" : 1372638979158
              },
              {
                  "token" : "EHgLLHMh6JWxKfuoe",
                  "when" : 1372825386462
              }
          ]
      }
  </code></pre>