comix library management should be more usable

[i30817]

Comix library management could be made more usable by adding support for 'subcollections', collections that are added automatically recursivelly if a directory is selected instead in addition to books

So a cbz directory has a few subdirectories, such as

Jennifer Blood
----- Jennifer Blood 01.cbz
----- First Blood (directory)

selecting both would mean that two new collections would be created
Jennifer Blood
and
Jennifer Blood: First Blood

(although i would prefer if it was a single collection, but with some kind of border with the name so we can tell when one starts and the next begins and comix can warn it's changing collection, and if the user wants that, when one reaches the end of the first).

[i30817 (i30817)]

Edit, never mind, just found the drag and drop of the Collection list. It could be made automatic with what i said, in the adding books dialog though.