ImageViewer is broken

[sebbert]

ImageViewer has a couple of bugs that I don't have the knowledge of how to fix.

• - Double tapping to reset the transform and the close button works only while interacting with the Rotate- Zoom- and RotateGestures.
• - Rotation gesture often wraps around, resulting in a rotation > 180°, instead of taking the shortest path.
• - A bunch of TODO comments and confusion regarding removed/renamed/deprecated features

Tested using Android preview, Fuse 0.26.0 (7741)

[bondehagen]

The gestures also feals very unnatural and weird.

[bondehagen]

@sebbert some of this is fixed in 7a78a08#diff-76f439ed0cffc2d7d6091816c835f426

[bondehagen]

Switching from portrait to landscape is messing up the layout when viewing an image

[kristianhasselknippe]

@eksperts will take a look at this today

[eksperts]

@bondehagen PR in: #59
First it's a general syntax cleanup and associated changes to match best practices.
Second, the RotateGesture wrap-around problem was caused by the StepDegrees property; removed it and it's now fine (tried, but could not find a way to eliminate wrap-around by leaving StepDegrees).
Could not reproduce the "double tapping" issue @sebbert mentioned, worked fine on a Nexus 5.