fix(package): fix imagemin for windows users

npm install sometimes freezes when installing imagemin for windows users.
Using older version of jpegtran fixes this.

gruntjs/grunt-contrib-imagemin#109

Author: DaftMonk

templates/common/_package.json

@@ -21,6 +21,7 @@
     "grunt-contrib-copy": "~0.4.1",
     "grunt-contrib-cssmin": "~0.7.0",
     "grunt-contrib-htmlmin": "~0.1.3",
+    "jpegtran-bin": "0.2.0",
     "grunt-contrib-imagemin": "~0.3.0",
     "grunt-contrib-jshint": "~0.7.1",
     "grunt-contrib-uglify": "~0.2.0",