Themes

- Added the new color.blocking to each theme.  In most cases it is the
  same as color.blocked, with something slightly 'bolder' about it, but
  in the more quirky ones it is the same.  These need tweaking.

doc/rc/dark-gray-256.theme

@@ -70,6 +70,7 @@ color.pri.M=color7
 color.pri.L=color8
 color.tagged=gray12
 color.blocked=color15 on color8
+color.blocking=color15 on color7
 color.project.none=
 color.tag.none=
 color.alternate=on gray2