Add filter for Closure functions

[akoryak]

What does this PR do?

Add filter for Closure functions

Checklist

• [ x ] Pull request contains a clear definition of changes
• [ x ] Tests (either unit, integration, or acceptance) written and passing
• [ x ] Relevant documentation produced and/or updated

[chadicus]

I'm not sure this is the right library for the closures filter class, but i'll defer to others.
Be sure to update the README.md file with instructions and usage examples

[akoryak]

I'm not sure this is the right library for the closures filter class, but i'll defer to others. Be sure to update the README.md file with instructions and usage examples

1. updated the documentation
2. It doesn't have much sense to me to create new git repository with ~90% duplication for just one simple filter function. Second reason I why I added it here is that I don't see any use case for this closure filter be used standalone