Better scribe handling using scribe "pools"

[iherman]

@bigbluehat,

I have added a new scribing model to the script, inspired by a similar change that has been done by the core scribe script that is also used elsewhere at W3C. This PR should not be merged yet, because I would prefer to test it a bit more, although it seems to work now, and I have also used it on the latest JSON-LD WG call minutes (I have just modified the log a bit to turn it into a test).

The new scribing approach is as follows.

• First of all, we can also use scribe instead of scribenick. Both are valid and have the same effect.
• The model is that, instead of having one active scribe, there is an active scribe “pool” for the call (elements of that pool are nicknames of participants who may act as scribes). There are three ways of setting/changing the pool:
  1. scribe+ nick1, nick2, ... adds nicknames to the pool. If no nickname is provided, the nickname of the issuer is used, much like using present+.
  2. scribe- nick1, nick2, ... removes nicknames to the pool; the no nickname case is handled like for scribe+
  3. scribe: nick1, nick2, ... sets the content of the pool from scratch; the no nickname case is handled like for scribe+
• Any scribe whose name is in the pool can scribe at any time, replacing one-another; those lines will all be considered as if the same and only one scribe had written the minutes

This change, while fully backward compatible with current practice. But it is very helpful when a temporary scribe replacement is needed, because the original scribe wants to say something:

<pchampin> scribenick: pchampin
...
<pchampin> bigbluehat: says something great
<rubenworks> scribe+
<rubenworks> pchampin: says something specific, not related to scribing, 
<rubenworks> ... and it is now part of the minutes
...
<pchampin> ivan: says something else (taking over minuting without further ado)
<pchampin> ... minutes are continued
<rubenworks> ... can be continued by the other scribe...

Note that it is no longer necessary to set <pchampin> scribenick: pchampin "back", and then again set it for Ruben, etc.

WDYT? Is this a worthwhile addition to the script or it would just mess up people? Is the functionality clear at least to you?

[iherman]

Modified the functionality a little bit in https://github.com/w3c/scribejs/pull/75/commits/abd5616fafcc084d27572fb340f506c8f66b0146: introduced 'command=' to wipe out old content, and 'command:' is equal to 'command+'. This is valid for all such terms, in particular to scribes.