Keep history of chapters in the quick chapter swapper

[tasomaniac]

A quick improvement for the long list of chapter in the MainActivity would be to keep a history of chapters that are manually selected before.

This was suggested by @rciovati in Gitter chat.

This is also related to #562

[tasomaniac]

@rciovati do you have time to work on this? If we just have history of items above the others, we can ask feedback about this to users.

[tasomaniac]

The new chapter selector dialog is very helpful. Maybe this is not a necessity anymore.

Btw, putting recently used ones on top is easy. But it may confuse users. We should have proper sections/dividers. I couldn't think of a straightforward solution to do that. Both implementation and design wise.