cli: Release the new decoupled version 0.15.0.

cli has now its own lifecycle,
installs always the newest amber, amber-dev
from repl and amberc,
and project from newest grunt-init-amber.

external/amber-cli/package.json

@@ -1,6 +1,6 @@
 {
   "name": "amber-cli",
-  "version": "0.15.0-1",
+  "version": "0.15.0",
   "description": "An implementation of the Smalltalk language that runs on top of the JS runtime.",
   "homepage": "http://amber-lang.net",
   "keywords": [