AMP (#8004) almost finished, review would be nice

[Edward Z. Yang]

Excerpts from David Luposchainsky's message of Tue Sep 03 07:40:38 -0700 2013:
> > I don't see any documentation.
> 
> In what sense? More comments, longer function headers? I thought the
> names used were clear, with comments giving an overview over longer
> sections. (If you're talking about Haddock: the AMP functions are not
> exported, hence no HTML docs. tcAmpWarn is called from inside
> tcTopSrcDecls in the same module.)

It's a command line flag, so the manual needs to be updated to describe
it. It also needs to be added to the changelog.

Cheers,
Edward