* 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
* Added circular thumbnails to the catalogue list view, like the ones in the library list view
* Moved setImage to CatalogueHolder parent class and adapted the code so that when the manga is initialized, the thumbnail is set both in the case of grid and list
* In catalog, when switching between grid and list, initialize mangas only if going to grid view or if over wifi
* Saving to SD working
* Rename imagePath to uri
* Handle android < 21
* Minor changes
* Separate downloader from the manager. Optimize folder lookups
* Persist downloads across restarts
* Fix for #511
* Updated ReactiveNetwork. Add some documentation
* More documentation and minor fixes
* Handle persistent notifications. Other minor changes
* Improve downloader and add documentation
* Rename pageNumber to index in Page class
* Remove unused methods
* Use chop method
* Make sure dest dir is created
* Reset downloads dir preference
* Use invalidate options menu in download fragment and fix wrong condition
* Fix empty download queue after application restart
* Use addAll method in download queue to avoid too many notifications
* Inform download manager changes
* Added in the ability to view the library as a list
* reverted LibraryAdapter and renamed libraryToggleViewEvent to LibraryToggleViewEvent for consistency
* removed LibraryToggleViewEvent and directly subscribed to option change
* fixed the toggleView subscription
* Made the library list item layout more compliant with material design
* Changed unread text style and removed background
