Add quality of service option to subscriptions

Fixes #323, #14, #334
Fixes #132

app/test/mocha.opts

@@ -0,0 +1,3 @@
+--require ts-node/register
+--require source-map-support/register
+--recursive ./src/**/*.spec.ts

app/test/tsconfig.json

@@ -0,0 +1,6 @@
+{
+  "extends": "../tsconfig",
+  "compilerOptions": {
+    "module": "commonjs"
+  }
+}