Add first batch of tests

package.json

@@ -10,6 +10,9 @@
     "type": "git",
     "url": "https://github.com/klokantech/tileserver-gl.git"
   },
+  "scripts": {
+    "test": "mocha test/**.js"
+  },
   "dependencies": {
     "async": "1.5.2",
     "advanced-pool": "0.3.1",
@@ -23,5 +26,10 @@
     "request": "2.69.0",
     "sharp": "0.13.1",
     "sphericalmercator": "1.0.4"
+  },
+  "devDependencies": {
+    "should": "^8.2.2",
+    "mocha": "^2.4.5",
+    "supertest": "^1.2.0"
   }
 }