Add -K (--ask-sudo-pass) flag to ansible-pull.

Until now, I comfortably used ansible-playbook in my personal workflow with the -K flag. I recently tried ansible-pull but soon realized that it lacks the -K flag and many other flags found in ansible-playbook. This simple commit adds the -K flag to ansible-pull. I tested it on my machine and it appears to work. Without it, I (and other users of the system) would need to run ansible-pull as a NOPASSWD user such as root, something I'd prefer not to do.

Since ansible-pull simply calls ansible-playbook, might it make sense for most, if not all, of the flags available in ansible-playbook to be available in ansible-pull?