Added better support for NODE_ENV

-The different methods of starting the explorer now set NODE_ENV to "development" or "production" depending on which options were chosen
-pm2 is now loaded from within the prestart script and will reload the config instead of starting if it was previously loaded which allows changing the NODE_ENV value if necessary

NOTE: if running via pm2 or forever when updating the explorer with this change, it is necessary to manually stop the explorer with `npm run stop-pm2` or `npm run stop-forever` and then start again after the code has been updated to allow NODE_ENV to be set to "production". Without doing this, the explorer will still be run in "development" mode until pm2 or forever is fully stopped and restarted.

package.json

@@ -6,11 +6,11 @@
     "start": "node --stack-size=10000 ./bin/cluster",
     "stop": "node ./scripts/stop_explorer.js",
     "start-instance": "npm run prestart && node --stack-size=10000 ./bin/cluster 1",
-    "start-forever": "npm run prestart \"forever\"",
+    "start-forever": "npm run prestart \"forever production\"",
     "stop-forever": "forever stop \"explorer\"",
     "reload-forever": "forever restart \"explorer\"",
-    "start-pm2": "npm run prestart \"pm2\" && pm2 start ./bin/instance -i 0 -n explorer -p \"./tmp/pm2.pid\" --node-args=\"--stack-size=10000\"",
-    "start-pm2-debug": "npm run prestart \"pm2\" && pm2 start ./bin/instance -i 0 -n explorer -p \"./tmp/pm2.pid\" --node-args=\"--stack-size=10000\" && pm2 logs",
+    "start-pm2": "npm run prestart \"pm2 production\"",
+    "start-pm2-debug": "npm run prestart \"pm2 development\" && pm2 logs",
     "stop-pm2": "pm2 stop explorer",
     "reload-pm2": "pm2 reload explorer",
     "test": "node ./node_modules/jasmine/bin/jasmine.js test/*Spec.js",