Move the Meteor configs, such as the root URL and production home directory, to NPM

This commit allows NPM to run the client in development and production modes using all the Meteor-related configs.

Run client in development:
NODE_ENV=development npm start
or
npm start

Run client in production:
NODE_ENV=production npm start

The default rootURL is http://127.0.0.1/html5client. This can be changed in .npmrc.
If prodHome is specified in .npmrc, then its value is used as Meteor's $HOME.

bigbluebutton-html5/.npmrc

+rootURL = http://127.0.0.1/html5client
+#prodHome = /usr/share/meteor
+

bigbluebutton-html5/package.json

@@ -2,9 +2,16 @@
   "name": "bbb-html5-client",
   "description": "BigBlueButton HTML5 Client",
   "scripts": {
-    "start": "if test \"$NODE_ENV\" = \"production\" ; then npm run start:production; else npm run start:development; fi",
-    "start:production": "./start.sh",
-    "start:development": "./start.sh",
+    "start": "if test \"$NODE_ENV\" = \"production\" ; then npm run start:prod; else npm run start:dev; fi",
+
+    "start:prod": "if test $npm_config_rootURL; then npm run start:prod:customRootURL; else npm run start:prod:defaultRootURL; fi",
+    "start:prod:customRootURL": "if test $npm_config_prodHome; then HOME=$npm_config_prodHome ROOT_URL=$npm_config_rootURL NODE_ENV=production meteor; else ROOT_URL=$npm_config_rootURL NODE_ENV=production meteor; fi",
+    "start:prod:defaultRootURL": "if test $npm_config_prodHome; then HOME=$npm_config_prodHome ROOT_URL=http://127.0.0.1/html5client NODE_ENV=production meteor; else ROOT_URL=http://127.0.0.1/html5client NODE_ENV=production meteor; fi",
+
+    "start:dev": "if test $npm_config_rootURL; then npm run start:dev:customRootURL; else npm run start:dev:defaultRootURL; fi",
+    "start:dev:customRootURL": "ROOT_URL=$npm_config_rootURL NODE_ENV=development meteor",
+    "start:dev:defaultRootURL": "ROOT_URL=http://127.0.0.1/html5client NODE_ENV=development meteor",
+
     "preinstall": "npm install grunt-cli",
     "test": "wdio ./tests/webdriverio/wdio.conf.js",
     "lint": "eslint . --ext .jsx,.js"