Added an ignored_directories option similar to ignore_files to allow for exclusion of directories

[fgimian]

Hey there again Domen :smile:

This pull request implements a similar flag to ignored_files called ignored_directories which allows you to exclude directories in much the same way as you can files. I needed this for my current project to exclude the .git directory and I'm sure others may find a similar use for it.

Huge credit to Godefroid Chapelle for making my life easy (since most my code is similar to his).

More pull requests to come :smile_cat:

Cheers Fotis

[domenkozar]

Thank you!