Better Offline Mode Stability for Charts

This past Sunday our ISP had an issue mid-service and our internet connection went down. While Presenter soldiered on, the Charts app on all of our team's iPads suddenly just showed a black rectangle where the chart should have been mid-song. All of us had to force-quit the app, wait for it to re-load, and then advance back to where were in the service.

While I appreciate that Charts had thankfully cached the service, we need it to not freak out on us and require a force-quit if there's a network connection issue.

Thanks in advance for helping to make this more stable!