Renames sftfilepath -> sftfilepattern

This renames the input sftfilepath to sftfilepattern and adds documentation on how that should be used, i.e. a colon separated list of wildstring or exact matches. In globbing for all matches, the colon split is added in. sftfilepath is still used by Writer since an exact path is known.

@dkeitel I've submitted this as a merge request to get your input, both because it effects a previous bug you fixed, and it may require you to rename a variable in all scripts (sftfilepath -> sftfilepattern). My reasoning is that the name better reflects its use: it will be more typical to provide a pattern than a path. Are you happy with this change?

Cheers,

Greg