Add mocha+wallaby tests

eventually the feature tests should be removed and most of our tests should become unit tests that are runnable from the command line or via wallaby.

npm run tdd will enable using mocha's command line tdd capability

README.md

@@ -3,6 +3,7 @@
 |Master|Release|
 |:--:|:--:|
 |[![Master Build Status](https://travis-ci.org/OmniSharp/omnisharp-vscode.svg?branch=master)](https://travis-ci.org/OmniSharp/omnisharp-vscode)|[![Release Build Status](https://travis-ci.org/OmniSharp/omnisharp-vscode.svg?branch=release)](https://travis-ci.org/OmniSharp/omnisharp-vscode)|
+[![Wallaby.js](https://img.shields.io/badge/wallaby.js-configured-green.svg)](https://wallabyjs.com)
 
 Welcome to the C# extension for Visual Studio Code! This preview provides the following features inside VS Code:
 

mocha.opts

@@ -0,0 +1,5 @@
+--ui tdd
+--require source-map-support/register
+--require ts-node/register
+
+test/unitTests/**/*.test.@(ts|tsx)