output source maps in a separate file

package.json

@@ -9,7 +9,7 @@
   "scripts": {
     "clean": "find dist -mindepth 1 -delete",
     "prebuild": "npm run clean & npm run test",
-    "build": "browserify -s Hls src/hls.js -o dist/hls.js",
+    "build": "browserify -s Hls src/hls.js --debug | exorcist dist/hls.js.map > dist/hls.js",
     "postbuild": "npm run minify",
     "minify": "uglifyjs dist/hls.js -c sequences=true,dead_code=true,conditionals=true,booleans=true,unused=true,if_return=true,join_vars=true,drop_console=true -m sort --screw-ie8 > dist/hls.min.js",
     "watch": "watchify --debug -s Hls src/hls.js -o dist/hls.js",
@@ -29,6 +29,7 @@
   "devDependencies": {
     "babelify": "^6.1.2",
     "browserify": "^8.1.1",
+    "exorcist": "^0.4.0",
     "http-server": "^0.7.4",
     "jshint": "^2.5.11",
     "live-reload": "^0.2.0",