Updated npm-watch Config with separate Tasks

package.json

{
  "watch": {
    "run_android": {
      "patterns": [
        "app"
      ],
      "extensions": "ts,html,scss",
      "quiet": true
    },
    "run_ios": {
      "patterns": [
        "app"
      ],
      "extensions": "ts,html,scss",
      "quiet": true
    }
  },
  "scripts": {
    "watch_android": "npm-watch run_android",
    "watch_ios": "npm-watch run_ios",
    "run_android": "tns run android --emulator",
    "run_ios": "tns run ios --emulator"
  }
}