Implement full screen photo feature

[wang-li]

The possibility to see a topo photo in full screen mode and zoom on it has been available in the iOS app for a long time, but still was not implemented in the android app.

full-screen-photo.mp4

The image can be zoomed by a pinch gesture or by a double tap.

Also, in the case of a missing boulder problem (highly unlikely, as the full screen photo has to be accessed from the topo of an already existing boulder problem), the following message will be shown:

Resolves #21

[nmondollot]

Looks good 👍

A few things:

• when I dismiss the full screen photo the map screen flickers (the area bar gets blank, the map gets gray), can we avoid that?
• is it possible to dismiss the full screen photo with a gesture? (or it is just on iPhone?)
• zoom: is it possible to make the line thinner as we zoom (similar to iPhone)?

Also, in the case of a missing boulder problem (highly unlikely, as the full screen photo has to be accessed from the topo of an already existing boulder problem), the following message will be shown:

"Boulder problem" sounds weird, let's say "This photo can't be displayed"

[wang-li]

@nmondollot All your feedback are fixed ✌️

full-screen-photo.mp4

[nmondollot]

Great!