Sync'em

Synchronizes multiple async calls, to return one callback when all are done. Our initial use case was synchronizing some DB calls with other async calls. Like so:

  function doMultipleThingsInParallel(){
    job.create(callback); // the `callback` is not synchronized with the `finalCallback` below
    upload.start(finalCallback);
  }

Syncem helps like this:

  function doMultipleThingsInParallel(){
    var sync = new SyncEm(finalCallback);
    job.create( sync.toBeSynced() );
    upload.start( sync.toBeSynced() );
  }

when both async jobs are done, the finalCallback is executed.