Add options for rule 'no-unused-vars' to check all arguments in functions (fixes #728)
update to latest Optionator

allows for multiple flags to array,
update env flag documentation to reflect this

closes #773
Merge pull request #774 from gkz/optionator-update

Update to latest Optionator
Merge pull request #771 from roadhump/issue_728

Add options for 'no-unused-vars' to check all arguments in functions (fixes #728)