[models] Remove incorrect documentation about supporting %f in NISliderFormElement.

Closes #455.
[catalog] Add an example clarifying how to chain actions and radio groups.

Closes #456.
[attributedlabel] Offset images to respect vertical alignment.

Closes #269.
[core] Make NIInMemoryCache thread-safe.
[photos] Ensure that UI-specific methods are executed on the main thread.
[core] Clean up the in memory caches with a fine-toothed comb.
[pagingscrollview] Refactor the classes and simplify the feature.
[pagingscrollview] Begin modernizing the source.
[pagingscrollview] Misc refactoring and clarification of names.
[pagingscrollview] More misc cleanup.
Fix doc style due to changes in Doxygen.