Run operations in a worker

package.json

@@ -26,6 +26,7 @@
   },
   "dependencies": {
     "async": "0.9.0",
+    "browserify": "9.0.3",
     "closure-util": "1.5.0",
     "fs-extra": "0.12.0",
     "glob": "5.0.3",
@@ -37,11 +38,11 @@
     "metalsmith": "1.6.0",
     "metalsmith-templates": "0.7.0",
     "nomnom": "1.8.0",
+    "pixelworks": "^0.8.0",
     "rbush": "1.3.5",
     "temp": "0.8.1",
     "walk": "2.3.4",
-    "wrench": "1.5.8",
-    "browserify": "9.0.3"
+    "wrench": "1.5.8"
   },
   "devDependencies": {
     "clean-css": "2.2.16",
@@ -61,6 +62,7 @@
     "slimerjs-edge": "0.10.0-pre-2"
   },
   "ext": [
-    "rbush"
+    "rbush",
+    {"module": "pixelworks", "browserify": true}
   ]
 }