better connection handling in QML UI

[Dirk Hohndel]

I just uploaded a new Android APK and pushed my changes to master.
Yes, this includes the change to the action button that makes it harder to
read - sorry, we'll address that. But what I'd like people to focus on and
play with is the change to the download dialog, where the connection is
now a third dimension. This is currently broken when used with "Paired
Bluetooth Devices" (because I want to remove that option), but it should
work well and do the "intuitive" thing when selecting a dive computer.

I'd appreciate some feedback on this :-)

http://subsurface-divelog.org/downloads/test/Subsurface-mobile-4.6.4.425-arm.apk

/D