adds "missing" alternate /a glyphs for superscript & subscript. Closes #456

Author: rsms

src/Inter-Roman.glyphspackage/fontinfo.plist

@@ -2878,6 +2878,8 @@ sub bracketright by bracketright.subs;
 sub plus by plus.subs;
 sub minus by minus.subs;
 sub equal by equal.subs;
+sub a.1 by a.1.subs;
+sub a.2 by a.2.subs;
 ";
 tag = subs;
 },
@@ -2926,6 +2928,8 @@ sub bracketright by bracketright.sups;
 sub plus by plus.sups;
 sub minus by minus.sups;
 sub equal by equal.sups;
+sub a.1 by a.1.sups;
+sub a.2 by a.2.sups;
 ";
 tag = sups;
 },

src/Inter-Roman.glyphspackage/glyphs/a.1.subs.glyph

@@ -0,0 +1,67 @@
+{
+case = minor;
+glyphname = a.1.subs;
+kernRight = zero.subs;
+layers = (
+{
+layerId = "C698F293-3EC0-4A5A-A3A0-0FDB1F5CF265";
+shapes = (
+{
+pos = (0,-1200);
+ref = a.1.sups;
+}
+);
+width = 896;
+},
+{
+layerId = "5C20EF92-B63D-42A8-8878-93C2863E0093";
+shapes = (
+{
+pos = (0,-1200);
+ref = a.1.sups;
+}
+);
+width = 973;
+},
+{
+layerId = "B1F27B51-9973-4381-9301-4FE46FE1CA59";
+shapes = (
+{
+pos = (0,-1200);
+ref = a.1.sups;
+}
+);
+width = 822;
+},
+{
+layerId = m007;
+shapes = (
+{
+pos = (0,-1200);
+ref = a.1.sups;
+}
+);
+width = 788;
+},
+{
+layerId = m009;
+shapes = (
+{
+pos = (0,-1200);
+ref = a.1.sups;
+}
+);
+width = 818;
+},
+{
+layerId = m011;
+shapes = (
+{
+pos = (0,-1200);
+ref = a.1.sups;
+}
+);
+width = 757;
+}
+);
+}