Update @angular/cli

Previously, an exported project threw an error when trying to build: cannot find module '@angular-devkit/core

This commit updates the @angular/cli package to a version which resolves this error as mentioned in: angular/angular-cli#9307

Author: frederikprijck

package.json

@@ -26,7 +26,7 @@
     "zone.js": "^0.8.4"
   },
   "devDependencies": {
-    "@angular/cli": "1.5.4",
+    "@angular/cli": "1.6.7",
     "@angular/compiler-cli": "^5.0.0",
     "@angular/language-service": "^5.0.0",
     "@types/jasmine": "~2.5.53",