Feature request: allow only valid file types

[felciano]

Given that there are upload limits using the Google Photos API, it would be nice to avoid uploading files that are known to be invalid file types. An example of this is .XMP files that are created when exporting a folder or album from Aperture, which one would then like to upload to Google Photos using gpup.

This could either be via an extensible list of file types (suffixes), or a simpler switch (e.g. --only-upload-known-media-types) if it is possible to pre-identify the filetypes that Google Photos accepts.

[jpg0]

FYI you can use either of the two PRs I made (#30, #31) to achieve this if you need now, by specifying the file types you want, either:

gpup --inc "\.jpg$" my_directory

or

find --name \*.jpg | gpup -

or you could even choose to exclude types that you don't want:

gpup --exc "\.XMP$" my_directory