* support for async cluster creation
* fix lintr bot errors
* remove test files
* use private function for duplicate code
* update change log
* Feature/asynccluster1 (#200)
* show node status in getCluster
* workaround error
* minor fixes
* add getClusterList api
* add metadata to pool indicating pool is created by doAzureParallel
* add test for getClusterList(), add 'other' state for nodes for getCluster()