chore: Update various dependencies

Update dev dependency:

* mocha 2.5.3 -> 4.1.0

Update dependency:

* chokidar 3.0.1 -> 3.0.2

The mocha udpate required a small change to the test file as mocha no
longer forces an exit once all tests have passed. So a file had to be
unwatched after the relevant test passed, or otherwise mocha would not
exit.

package.json

@@ -37,18 +37,18 @@
     "chai": "3.5.0",
     "eslint": "2.13.1",
     "jsdoc": "3.6.2",
-    "mocha": "2.5.3",
     "nyc": "14.1.1",
     "sinon": "1.17.4",
     "touch": "1.0.0"
   },
   "dependencies": {
     "async": "1.5.2",
     "chalk": "1.1.3",
-    "chokidar": "3.0.1",
+    "chokidar": "3.0.2",
     "columnify": "1.5.4",
     "glob": "7.0.4",
     "lodash.defaults": "4.2.0",
+    "mocha": "4.1.0",
     "stampit": "1.2.0",
     "strip-json-comments": "2.0.1",
     "user-home": "2.0.0",