work on new eval-viz layer stringification which factors out measurement/limiting/etc., but just walks an eval tree and stringifies each part; start working on new types <-> lookup-rule stuff

src/base/base_meta.h

@@ -100,10 +100,9 @@ TypeKind;
 typedef U32 TypeFlags;
 enum
 {
-  TypeFlag_IsExternal  = (1<<0),
-  TypeFlag_IsPlainText = (1<<1),
-  TypeFlag_IsCodeText  = (1<<2),
-  TypeFlag_IsPathText  = (1<<3),
+  TypeFlag_IsPlainText = (1<<0),
+  TypeFlag_IsCodeText  = (1<<1),
+  TypeFlag_IsPathText  = (1<<2),
 };
 
 typedef U32 MemberFlags;