#43 Scripting command mask character

[Martin Moore]

It would be nice to be able to define a "mask" character
for scripting commands. If input starts with this
character the input is not sent to the chat channel.

eg:

configfile: script_command_char=$

Then when a user types: $help in chat, this is not
displayed in the chat at all but it is sent to the function
int command_arrival(user, command, extra) in all scripts.

Further to this, it might be nice to handle a return from
this sub. So if all scripts called return 0, then the text
sent is considered to not be a command at all and is
sent to chat. However, if one (or more) script
recognises the input text as a command, it shall return a
1 from the command_arrival() function, preventing the
text from ever being echoed to the chat window.