Do not pass redundant argument to superclass init.
Make abstract methods raise NotImplementedError.
Rudimentary unit tests for DataStore.
Merge pull request #792 from Renelvon/fix_bad_arg

Fix node not starting.
Preliminary fixes and grooming.

* Drop duplicate `-bmX` flags.
* Fix bad initialization of http_ip and http_port.
* Add missing default DEV_NODES.
* Delete unused default NODES.
* Add module docstring and parser desription.
* Do not parrot commands to output.
* Align arguments and keys.
* Have parser check commands.
* Drop `status` command.
* Fix bad combination of `with` and `try`.
* Tidy imports.
Group switches by type.
Derive key from argument automatically.