resolves #766 suggest to users run --help command

[GeorgeGkas]

Adding one more console.error statements to bellow methods:

• Command.prototype.missingArgument
• Command.prototype.optionMissingArgument
• Command.prototype.unknownOption
• Command.prototype.variadicArgNotLast

This console.error messages propose to user run the same command
with --help option to get more info about the command which try
to run. This is something that most UNIX like commands do
(like rm, cp, mv, etc)

[shadowspawn]

I am closing this PR as has not had recent activity and there are multiple conflicts, and it is a simple change so easier to make it again fresh after discussing desired error format in #766.

I found there is already one error in commander which suggests trying --help and on a single line like git does. I think this is probably tidier, but have not worked through all four cases that are in this PR to check it will look ok.

      console.error('error: %s(1) does not exist, try --help', bin);

Thank you for your contributions.