Fix filenignore behavior for directories

[szapp]

As by gitignore syntax, directories are differentiated from files by specifying a trailing slash.

any_directory/
any_file
/specific/directory/
/specific/file

Filen's sync does not meet these specifications and fails to match entries with trailing slash. Instead, for the example above, Filen would not ignore the directories until removing the trailing slash. Although seemingly not a big problem, it is not the gititnore behavior and may lead to confusion and frustration.

The reason is laid out in the README ("2. filenames and dirnames") of the used package ignore: The package cannot tell files and directories apart given the file path as simple string and requires a trailing slash to do so.

Here, I attempted to remedy this behavior at the relevant portions in the code that I could find by passing a trailing slash to the ignores function. Most likely that is not done in the most performant and elegant way. Nevertheless, I hope it will inspire to address this minor issue.

[Dwynr]

LGTM, will run it on a separate branch before merging (+ make it a bit more peformant). Thanks!