Merge pull request #1906 from dpvc/issue1819

Have \bigg and friends to trim spaces from their arguments.  #1819

Author: dpvc

unpacked/jax/input/TeX/jax.js

@@ -2037,8 +2037,12 @@
       while (this.nextIsSpace()) {this.i++}
       var c = this.string.charAt(this.i); this.i++;
       if (this.i <= this.string.length) {
-        if (c == "\\") {c += this.GetCS(name)}
-        else if (c === "{" && braceOK) {this.i--; c = this.GetArgument(name)}
+        if (c == "\\") {
+          c += this.GetCS(name);
+        } else if (c === "{" && braceOK) {
+          this.i--;
+          c = this.GetArgument(name).replace(/^\s+/,'').replace(/\s+$/,'');
+        }
         if (TEXDEF.delimiter[c] != null) {return this.convertDelimiter(c)}
       }
       TEX.Error(["MissingOrUnrecognizedDelim",