[MERGE] Make the plugins command public with better help

[John Arbash Meinel]

John Arbash Meinel has voted +1 (conditional).
Status is now: Semi-approved
Comment:
I think Aaron has valid concern about command count. But I also think 
'bzr plugins' and 'bzr help plugins' are good things to have.
So +1 on the help documentation.
I'm probably slightly more in favor of exposing plugins than hiding it, 
but probably not enough to override Aaron without more discussion.


For details, see: 
http://bundlebuggy.aaronbentley.com/request/%3C46973D73.4070406%40internode.on.net%3E