allow to exclude path for meta-header

|Q            |A  |
|---          |---|
|Bug Fix?     |no |
|New Feature? |yes|
|BC Breaks?   |no |
|Deprecations?|no |
|Tests Pass?  |yes|
|Fixed Tickets|   |
|License      |MIT|

This add the originally requested feature for excluding files for the `meta:header` command - #277 

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Should this be above the assignment?