BUG: Allow broadcast messages beginning with command keywords

Bug Description

• SYMPTOM: I am an admin on a channel and I send "Hello everyone!" I expect that message to be broadcast, but instead i get a "You are already a member" message.
• CAUSE: the regex that matches commands currently matches on a command keyword and any number of subsequent characters
• FIX: the regex that matches 1-word commands (ie: commands without a payload like HELLO/GOODBYE/INFO/RESPONSES ON/RESPONSES OFF) should only match on the keyword (after stripping whitespace)

Desired Behavior

• GIVEN an admin on a channel
• WHEN I send any of the following:
  • hello foo
  • goodbye foo
  • info is on the way
  • responses on now!
  • responses off now!
• THEN that message should be broadcast to all members of the channel