Adding section to guard jQuery for development.

Now that Helios is moved out and not installed via bower,
so are gone its (or more precisely, bootstrap2's) restrictions on jQuery version.

To keep these restrictions, they are added as devDependencies,
so in production amber is not restricted, but in development,
it copied bootstrap2's constraints..

bower.json

@@ -20,5 +20,8 @@
     "es5-shim": "~3.3.0",
     "codemirror": "~3.24.0",
     "require-css": "~0.1.2"
+  },
+  "devDependencies": {
+    "jquery": ">=1.7.0 <2.1.0"
   }
 }