Adopt monaco-editor-core@0.5.1

package.json

@@ -25,7 +25,7 @@
     "jsdom-no-contextify": "^3.1.0",
     "merge-stream": "^1.0.0",
     "mocha": "^2.5.3",
-    "monaco-editor-core": "^0.4.0",
+    "monaco-editor-core": "0.5.1",
     "object-assign": "^4.1.0",
     "rimraf": "^2.5.2",
     "typescript": "^1.8.10",