[CN] More flexible --skip command

[peterohanley]

I would like --skip to allow arguments to be regular expressions, and if possible some kind of --skip-file argument that skips all functions with their declaration in a given file (also a regex, and known from source information). This will be useful for specification of small parts of large projects, especially when there are inline definitions in headers that do not pass CN checking.

[podhrmic]

@thatplguy this is important for analyzing the Lynx OS code

[dc-mak]

Related: #314