Make the path argument accept multiple paths or add subset option

[zachary-foster]

Currently, the path can only accept one path. It would be useful if it could accept multiple paths since it would allow for an easy way of only quilting parts of a directory. However, the path argument currently is used to identify the "root" config file that can be used to define the options that are not file-path-specific. If there are multiple paths, where to look for these options is ambiguous. Perhaps it could look in the shared directory of all paths.

Alternatively, a new option called subset could be added to perform this function.