Make thumbnail updates when scrolling go from first to last, not reverse.

What we want to achieve here is:
1. Once user scrolls, we want to start showing thumbnails for items
visible after scroll ASAP.
2. We want to show them from beginning to end, not the other way around
as was in original ComicsReader.
3. But first line may be almost completely obscured, so no actual thumbs
is visible on it (only text titles), so we want to skip them.
4. Or first line may be only partially obscure, and small part of thumb
may be visible. In this case, we want to start with fully visible lines,
but get back to first partial line in the end.
Add PhotoView-based image sequence browse implementation.

https://github.com/chrisbanes/PhotoView

To get mouse wheel support, use https://github.com/pfalcon/PhotoView fork.
Add PhotoViewActivity, comment out old ViewerActivity.

They actually can remain both, and user will be offered both to view
images by intent type, both will work, but that's confusing.
Add PhotoView reference and bump target API.

android-12 is minimal API to use mouse wheel.
Update strings for PhotoTvViewer fork.
Update translations for PhotoTvViewer fork.
Remove autogenerated files.

Yes, it's ok to regenerate build.xml from scratch.