Replace istanbul with nyc

Use nyc instead of istanbul as the later has been deprecated and is no
longer being developed.  Fix the cover and test scripts to work again
with nyc and add the output dir for nyc into .gitignore.

.gitignore

@@ -11,8 +11,9 @@ pids
 # Directory for instrumented libs generated by jscoverage/JSCover
 lib-cov
 
-# Coverage directory used by tools like istanbul
+# Coverage directories used by tools like nyc and codecov
 coverage
+.nyc_output
 
 # Grunt intermediate storage (http://gruntjs.com/creating-plugins#storing-task-files)
 .grunt

package.json

@@ -5,9 +5,9 @@
   "repository": "https://github.com/Danielv123/factorioClusterio",
   "main": "master.js",
   "scripts": {
-    "test": "./node_modules/.bin/istanbul cover ./node_modules/mocha/bin/_mocha -- \"./{,!(node_modules)/**/}*.spec.js\" -R spec || echo .",
+    "test": "mocha -R spec -- \"./{,!(node_modules)/**/}*.spec.js\" || true",
+    "cover": "nyc --reporter=lcovonly npm run-script test && codecov -f coverage/lcov.info -t f7b38085-36eb-4d72-84e6-64721910171e",
     "start": "echo Run node client.js start [instance] to start slaves && node master.js",
-    "cover": "./node_modules/.bin/istanbul cover ./node_modules/mocha/bin/_mocha -- \"./{,!(node_modules)/**/}*.spec.js\" -R spec || echo . && codecov -t f7b38085-36eb-4d72-84e6-64721910171e",
     "install": "node lib/npmPostinstall.js",
     "bundle-dependencies": "bundle-dependencies"
   },
@@ -64,11 +64,11 @@
   },
   "devDependencies": {
     "html5-validator": "^1.0.7",
-    "istanbul": "^0.4.5",
     "mocha": "^3.5.3",
     "mocha-sinon": "^2.0.0",
     "mocha.parallel": "^0.15.5",
     "nock": "^9.1.6",
+    "nyc": "^14.1.1",
     "sinon": "^2.4.1",
     "supertest": "^3.0.0"
   }