new keyword: probation

[Alexandre Wajnberg]

> 
> I'm going to try the following: sequences of doubtful value
> will get a new keyword:  probation.  I hope that the associate editors
> and other seqfans will look at these from time to time,
> and either edit them or suggest that they be removed.
> 
> After a while, if noone votes for keeping them, they will be removed.

And what if sequences haven't received votes for keeping them, but haven't
been looked at? "after a while".

[I suppose "after a while" is only a part of the (in)validation process, so
that sequences not yet looked at will appear as such: still waiting for a
look before to be possibly rejected]