Add purescript to depDependencies

Author: felixSchl

package.json

@@ -11,6 +11,7 @@
     "gulp": "^3.9.0",
     "gulp-purescript": "^0.5.0-rc.1",
     "gulp-run": "^1.6.8",
-    "lodash": "^3.9.3"
+    "lodash": "^3.9.3",
+    "purescript": "^0.7.4-rc.1"
   }
 }