Created two new helper functions to create a `cli.Context` with and without a
`cli.App`.
Calling these functions simplifies a lot of test code.
Signed-off-by: James O. D. Hunt <james.o.hunt@intel.com>
Events cli display container events such as cpu,
memory, and IO usage statistics.
By now OOM notifications and intel RDT are not fully supproted.
Fixes: #186
Signed-off-by: Haomin <caihaomin@huawei.com>