scripts: Adopted Attr rework in plot.py/plotmpl.py

Unifying these complicated attr-assigning flags across all the scripts
is the main benefit of the new internal Attr system.

The only tricky bit is we need to somehow keep track of all input fields
in case % modifiers reference fields, when we could previously discard
non-data fields.

Tricky but doable.

Updated flags:

- -L/--label -> -L/--add-label
- --colors -> -C/--add-color
- --formats -> -F/--add-format
- --chars -> -*/--add-char/--chars
- --line-chars -> -_/--add-line-char/--line-chars

I've also tweaked Attr to accept glob matches when figuring out group
assignments. This is useful for matching slightly different, but
similarly named results in our benchmark scripts.

There's probably a clever way to do this by injecting new by fields with
csv.py, but just adding globbing is simpler and makes attr assignment
even more flexible.

scripts/test.py

@@ -897,11 +897,11 @@ def find_ids(runner, test_ids=[], **args):
         if '*' in name:
             test_ids__.extend(suite
                     for suite in expected_suite_perms.keys()
-                    if fnmatch.fnmatch(suite, name))
+                    if fnmatch.fnmatchcase(suite, name))
             if not test_ids__:
                 test_ids__.extend(case_
                         for case_ in expected_case_perms.keys()
-                        if fnmatch.fnmatch(case_, name))
+                        if fnmatch.fnmatchcase(case_, name))
         # literal suite
         elif name in expected_suite_perms:
             test_ids__.append(id)