Bug: Android back button leaves dialog open

[AlexMcConnell]

Load up the example app on Android. Go to the examples page and open any of the dialogs. Click the Android back button. The page navigates back, but the dialog is still open. The user can close it from there, but that's pretty awful UX.

[sososdk]

When persistent is true, the dialogs is global.

Set persistent to false, the FlashDialog will add to route, and can be closed through the back button.

Please refer to the usage of persistent.

[AlexMcConnell]

Which in turn requires me to add a bunch of Overlay code. :-\

Maybe it's not technically a bug, but I don't like it. :D