* cover caching overhaul
* add ui for removing custom cover
* skip some loading work
* minor cleanup
* allow refresh library metadata to refresh local manga
* rename metadata_date to cover_last_modified
* rearrange removeMangaFromLibrary
* change custom cover directory
add setting for updating cover when refreshing library
* remove toggle and explicit action for updating covers
* Use a wrapper around Manga to supply glide with proper equals() and hashCode() impl. for caching
* reload image if url has changed
* ignore case for http scheme comparison
* more ignore case for http scheme comparison
* fix indenting
* use data class for MangaThumbnail
* Delete old reader
* Add utility methods
* Update dependencies
* Add new reader
* Update tracking services. Extract transition strings into resources
* Restore delete read chapters
* Documentation and some minor changes
* Remove content providers for compressed files, they are not needed anymore
* Update subsampling. New changes allow to parse magic numbers and decode tiles with a single stream. Drop support for custom image decoders. Other minor fixes
* add local source
* small fixes
* change Chapter to SChapter and and Manga to SManga in ChapterRecognition.
Use ChapterRecognition.parseChapterNumber() to recognize chapter numbers.
* use thread poll
* update isImage()
* add isImage() function to DiskUtil
* improve cover handling
* Support external SD cards
* use R.string.app_name as root folder name
