Fetching CNContacts in the background + Select all button visibility fixed.

[kutakmir]

[dragosrobertn]

Hi @kutakmir, Thanks for your contribution, I am happy to look into it, could you please provide a description into why you want these changes made and the benefits of them?

I would also really appreciate a same code block to understand how you use it so I can add it to the readme.

Once I have those I can review and merge your PR. Dragos