remove non working dependency for win build

Author: robhrt7

package.json

@@ -61,7 +61,6 @@
   "devDependencies": {
     "assert": "~1.1.1",
     "cross-spawn": "^0.4.0",
-    "grunt-casperjs": "^2.1.0",
     "grunt-mocha-test": "^0.12.4",
     "mocha": "^2.0.1",
     "should": "~4.0.4",