scripts: Tweaked -./-p/-P flags in ascii scripts

- -*/--add-char/--chars -> -./--add-char/--chars
- -./--points -> -p/--points
- -!/--points-and-lines -> -P/--points-and-lines

Also fixed an issue in plot.py/Attr where non-list default were failing
to concatenate.

scripts/treemapd3.py

@@ -181,7 +181,7 @@ class Attr:
                     not isinstance(attr, tuple)
                         or attr[0] in {None, (), ('*',)}
                     for attr in (attrs or []))):
-            attrs = defaults + (attrs or [])
+            attrs = list(defaults) + (attrs or [])
 
         # normalize
         self.attrs = []