Add Option.implies()

[shadowspawn]

Pull Request

Problem

See: #1358

Solution

Add support for supplying a hash of implied option values. Add implementation support to have separate implied options for positive and negative dual options.

Details:

• a default value does not trigger implied values
• support all option types for source option, and for implied option
• the implied value overrides a default value, but not other option sources
• a dual positive and negative option have separate implied options
• not adding to help (leaving it up client to describe if desired)

Side notes:

• switched to console for code blocks with mixed commands and output for nicer display in README
• use sh rather than bash for code blocks which don't show output

ChangeLog

• add Option.implies() to set other option values when the option is specified

[abetomo]

LGTM

[shadowspawn]

I have added extra code to support separate treatment of positive and negative dual options based on the stored option values. (In future, this might be used to expand the .conflicts() support in similar way.)

[shadowspawn]

Marked for re-review after the additions. (Thanks for initial review too.)

[shadowspawn]

Back to draft. Improving examples, and looking into interaction with .conflicts() and .requiredOption().

[shadowspawn]

Sorted again!

[abetomo]

awesome!