adding -K flag for ask-sudo-pass to ansible-pull

##### Issue Type:

Feature Pull Request

##### Ansible Version:

ansible 1.4.4

##### Environment:

Generic feature request, but I'm using Ubuntu 12.04

##### Summary:

Resubmission of pull request #4945.
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. 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?

##### Steps To Reproduce:

ansible-pull -K ...

##### Expected Results:

ansible-pull -K asks for sudo password

##### Actual Results:

ansible-pull: error: no such option: -K