Updated portfile.7 man page - please review/commit

[Mark Duling]

Ok, so I've updated the portfile.7 manpage following James' instructions
and attached it to this bug:

http://trac.macosforge.org/projects/macports/ticket/4905

It adds:

-startupitems.keywords
-cvs.root key
-svn fetch section

and modifies:

-changes occurrances of DarwinPorts to MacPorts
-reworks dependency section to reflect new default port:<port> style

How can I get this reviewed and committed to HEAD?

Mark