openwhisk command usage bugs

[myan9]

This command is wrong with insufficient arguments, but the error message is weird. We should provide clearer usage helper message.

[myan9]

There's another usage issue here:
This command requires 1 parameter, but you provided none
should be:
This command requires 2 parameters, but you provided none

[myan9]

For now, not every clickable field in the usage model redirects us to a correct command. We should make sure that either the entity is not clickable or users can click the entity to get some correct command. Also, when users click an entity in usage model, maybe it's more reasonable to just promote the command in the REPL instead of executing the command.

[starpit]

moving to kui-shell/oui#60