revision: introduce --exclude=<glob> to tame wildcards

People often find "git log --branches" etc. that includes _all_
branches is cumbersome to use when they want to grab most but except
some.  The same applies to --tags, --all and --glob.

Teach the revision machinery to remember patterns, and then upon the
next such a globbing option, exclude those that match the pattern.

With this, I can view only my integration branches (e.g. maint,
master, etc.) without topic branches, which are named after two
letters from primary authors' names, slash and topic name.

    git rev-list --no-walk --exclude=??/* --branches |
    git name-rev --refs refs/heads/* --stdin

This one shows things reachable from local and remote branches that
have not been merged to the integration branches.

    git log --remotes --branches --not --exclude=??/* --branches

It may be a bit rough around the edges, in that the pattern to give
the exclude option depends on what globbing option follows.  In
these examples, the pattern "??/*" is used, not "refs/heads/??/*",
because the globbing option that follows the -"-exclude=<pattern>"
is "--branches".  As each use of globbing option resets previously
set "--exclude", this may not be such a bad thing, though.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

revision.h

@@ -59,6 +59,9 @@ struct rev_info {
 	/* The end-points specified by the end user */
 	struct rev_cmdline_info cmdline;
 
+	/* excluding from --branches, --refs, etc. expansion */
+	struct string_list *ref_excludes;
+
 	/* Basic information */
 	const char *prefix;
 	const char *def;