magic-string should be devDependency, because it gets bundled

package.json

@@ -49,7 +49,7 @@
     "eslint": "^2.9.0",
     "estree-walker": "^0.2.0",
     "istanbul": "^0.4.0",
-    "magic-string": "^0.10.1",
+    "magic-string": "^0.15.0",
     "mocha": "^2.3.3",
     "remap-istanbul": "^0.5.1",
     "rollup": "^0.26.2",
@@ -63,7 +63,6 @@
   },
   "dependencies": {
     "chalk": "^1.1.1",
-    "magic-string": "^0.15.0",
     "minimist": "^1.2.0",
     "source-map-support": "^0.4.0"
   },