devkit release 0.5.0: uses NodePlatform

Breaking change for Amber <= 0.14.13, so bumping 4 to 5.

external/amber-dev/package.json

@@ -1,6 +1,6 @@
 {
   "name": "amber-dev",
-  "version": "0.4.0",
+  "version": "0.5.0",
   "description": "Development goodies for Amber Smalltalk",
   "scripts": {
     "test": "echo \"Error: no test specified\" && exit 1"

package.json

@@ -29,7 +29,7 @@
     "test": "grunt test && cd external && cd amber-cli && npm test && cd .. && cd .."
   },
   "devDependencies": {
-    "amber-dev": "^0.4.0",
+    "amber-dev": "^0.5.0",
     "grunt": "^0.4.0",
     "grunt-contrib-clean": "^0.6.0",
     "grunt-contrib-jshint": "^0.11.0",