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.

dockers/texcmp/texcmp.js

@@ -49,7 +49,7 @@ Q.all([
     readFile(path.join(ssDir, "test.tex"), "utf-8"),
     ensureDir(tmpDir),
     ensureDir(teximgDir),
-    ensureDir(diffDir)
+    ensureDir(diffDir),
 ]).spread(function(data) {
     template = data;
     // dirs have been created, template has been read, now rasterize.
@@ -80,14 +80,14 @@ function processTestCase(key) {
     var fftLatex = writeFile(texFile, tex).then(function() {
         // Step 2: call "pdflatex key" to create key.pdf
         return execFile("pdflatex", [
-            "-interaction", "nonstopmode", key
+            "-interaction", "nonstopmode", key,
         ], {cwd: tmpDir});
     }).then(function() {
         console.log("Typeset " + key);
         // Step 3: call "convert ... key.pdf key.png" to create key.png
         return execFile("convert", [
             "-density", dpi, "-units", "PixelsPerInch", "-flatten",
-            "-depth", "8", pdfFile, pngFile
+            "-depth", "8", pdfFile, pngFile,
         ]);
     }).then(function() {
         console.log("Rasterized " + key);
@@ -168,7 +168,7 @@ function processTestCase(key) {
             // First image is red, second green, third blue channel of result
             "-channel", "RGB", "-combine",
             "-trim",  // remove everything with the same color as the corners
-            diffFile // output file name
+            diffFile, // output file name
         ]);
     }).then(function() {
         console.log("Compared " + key);
@@ -245,7 +245,7 @@ function fftImage(image) {
         real: real,
         imag: imag,
         width: image.width,
-        height: image.height
+        height: image.height,
     };
 }