Use css to initially scale on zoom.
Simplify the output scale for css zoom.
Merge pull request #3727 from brendandahl/css-zoom2

Use css to initially scale on zoom.
Trivial typo fix
Merge pull request #3790 from timvandermeij/typo-fix

Trivial typo fix
Refactoring thumbnail scroll code to fix jumps
Merge pull request #3776 from timvandermeij/thumbnail-jump

Refactoring thumbnail scroll code to fix jumps