Add Clusterio Library mod

Add a library mod for wrapping the Clusterio remote API and providing
related utilities.  This eases development of Clusterio related Lua code
by providing the same interface for both mods and modules and also makes
the serialize library available without having to duplicate it.

It is not possible to implement this through save patching as mods
cannot load Lua code from the level code like they can with code from
other mods.

package.json

@@ -69,6 +69,7 @@
   },
   "devDependencies": {
     "html5-validator": "^1.2.1",
+    "klaw": "^3.0.0",
     "mocha": "^6.2.0",
     "mocha-sinon": "^2.1.0",
     "mocha.parallel": "^0.15.5",