Use new constants stucture.

Disable tests for refactor.
Assert on unimplemented error.
Rewrite arity logic, use new command defs.

Handle quit special case, improve auth arity test (uses arity
validation).
Move unimplemented test spec.
Enable all commands for test environment.
0.1.1
Validate subcommand arity.
Update tests.
Assert on client/list.
0.1.2
Update deps.
0.1.3