Stop app crash when background service not available

This source:

```
Intent i = new Intent(this, PriceAlertsService.class);
startService(i);
```

In HomeActivity crashes when the phone doesn't allow background services. Wrap in exception handler so if user has prevented background services the app doesn't crash.

I'm marking as high priority (@hboon - I think it's high priority as a user is having their app crash at startup).