scripts/get_maintainer.pl: add maintainers in order listed in matched section

Previous behavior was "bottom-up" in each section from the pattern "F:"
entry that matched.  Now information is entered into the various lists in
the "as entered" order for each matched section.

This also allows the F: entry to be put anywhere in a section, not just as
the last entries in the section.

And a couple of improvements:

Don't alphabetically sort before outputting the matched scm, status,
subsystem and web sections.

Ignore content after a single email address so these entries are acceptable
M:	name <address> whatever other comment

And a fix:

Make an M: entry without a name again use the name from an immediately
preceding P: line if it exists.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>