Changes in version 1.0.4
Changes:
    + All generics have signature now
    + Add a cleanup function to `stopCluster`
    + Add the missing vignette
    + The server status has been changed to `connected` and `not connected`

                          Changes in version 1.0.3
Changes:
    + The reference arguments passed to makeDockerCluster will be copied before using.
    + Add `deep` parameter to `cleanupDockerCluster`
    + add cleanup function to cluster

                          Changes in version 1.0.2
New features:
    + Add "getDockerStaticData" and "setDockerStaticData"
Changes:
    + Cluster will not try to manage the worker and server handle
    + instance handles must be character now
    + Remove `addWorkers` and `removeWorkers` from the cluster. The worker number should be adjusted by `setWorkerNumber`
    + rename `initializeProvider` to `initializeCloudProvider`
    + The server container cannot be NULL

                          Changes in version 1.0.1
+ Change the arguments in clusterPreset to make its meaning more clear.
+ Add jobQueueName argument to makeDockerCluster
+ Add `setDockerWorkerNumber` to support kubernetes provider

                          Changes in version 1.0.0
First public release.