How can an admin remove a subscriber?

[spalmertwilio]

Support ticket 1228900 requested the following functionality:

An admin sends a text to Twilio number:

remove {subscriber-phone-number}

and then the subscriber is removed from the broadcast list.

[speedy01]

@kwhinnery
This would be a very helpful feature. Any idea on an ETA or if I can provide a bounty to get this done quickly? A blacklist feature would also be benificial..thanks!