Revert "Remove trailing commas for IE 9 compatibility"

This reverts commit 4d2e46e7f6.

Having trailing commans makes diffs easier to read as it avoids modifying a
line just to add a trailing comma if there is another item to add at the end
of a list.  There are plans to switch to ES6 notation and to translate that
to ES5 as part of the build process.  Since that translation would remove
trailing commas, the IE9 problems that originally motivated the commit
should vanish soon.

src/delimiter.js

@@ -331,7 +331,7 @@ var stackLargeDelimiters = [
     "(", ")", "[", "\\lbrack", "]", "\\rbrack",
     "\\{", "\\lbrace", "\\}", "\\rbrace",
     "\\lfloor", "\\rfloor", "\\lceil", "\\rceil",
-    "\\surd"
+    "\\surd",
 ];
 
 // delimiters that always stack
@@ -340,12 +340,12 @@ var stackAlwaysDelimiters = [
     "\\Uparrow", "\\Downarrow", "\\Updownarrow",
     "|", "\\|", "\\vert", "\\Vert",
     "\\lvert", "\\rvert", "\\lVert", "\\rVert",
-    "\\lgroup", "\\rgroup", "\\lmoustache", "\\rmoustache"
+    "\\lgroup", "\\rgroup", "\\lmoustache", "\\rmoustache",
 ];
 
 // and delimiters that never stack
 var stackNeverDelimiters = [
-    "<", ">", "\\langle", "\\rangle", "/", "\\backslash", "\\lt", "\\gt"
+    "<", ">", "\\langle", "\\rangle", "/", "\\backslash", "\\lt", "\\gt",
 ];
 
 // Metrics of the different sizes. Found by looking at TeX's output of
@@ -396,7 +396,7 @@ var stackNeverDelimiterSequence = [
     {type: "large", size: 1},
     {type: "large", size: 2},
     {type: "large", size: 3},
-    {type: "large", size: 4}
+    {type: "large", size: 4},
 ];
 
 // Delimiters that always stack try the small delimiters first, then stack
@@ -404,7 +404,7 @@ var stackAlwaysDelimiterSequence = [
     {type: "small", style: Style.SCRIPTSCRIPT},
     {type: "small", style: Style.SCRIPT},
     {type: "small", style: Style.TEXT},
-    {type: "stack"}
+    {type: "stack"},
 ];
 
 // Delimiters that stack when large try the small and then large delimiters, and
@@ -417,7 +417,7 @@ var stackLargeDelimiterSequence = [
     {type: "large", size: 2},
     {type: "large", size: 3},
     {type: "large", size: 4},
-    {type: "stack"}
+    {type: "stack"},
 ];
 
 /**
@@ -546,5 +546,5 @@ var makeLeftRightDelim = function(delim, height, depth, options, mode,
 module.exports = {
     sizedDelim: makeSizedDelim,
     customSizedDelim: makeCustomSizedDelim,
-    leftRightDelim: makeLeftRightDelim
+    leftRightDelim: makeLeftRightDelim,
 };