Explicitly list what we want in our NPM package

Switch over to explicitly listing what we want to include, rather
than listing what we don't want to include. There is too much risk
of getting random junk from your working copy otherwise. This should
also hopefully complain if something is missing.

package.json

@@ -3,9 +3,20 @@
   "version": "1.0.0",
   "description": "An HTML5 VNC client",
   "directories": {
+    "lib": "lib",
     "doc": "docs",
     "test": "tests"
   },
+  "files": [
+    "lib",
+    "AUTHORS",
+    "VERSION",
+    "docs/API.md",
+    "docs/LIBRARY.md",
+    "docs/LICENSE*",
+    "core",
+    "vendor/pako"
+  ],
   "scripts": {
     "lint": "eslint app core po tests utils",
     "test": "karma start karma.conf.js",