Make \big and its relatives use script or scriptscript fonts (although size is still absolute, as it is in TeX) so that it balances the text weight in scripts. Resolves issue #350.

unpacked/jax/input/TeX/jax.js

@@ -1503,7 +1503,7 @@
       size = String(size).replace(/(\.\d\d\d).+/,'$1')+"em";
       var delim = this.GetDelimiter(name);
       this.Push(MML.TeXAtom(MML.mo(delim).With({
-        minsize: size, maxsize: size, scriptlevel: 0,
+        minsize: size, maxsize: size, //scriptlevel: 0,
         fence: true, stretchy: true, symmetric: true
       })).With({texClass: mclass}));
     },