Migrate the remaining classes to Kotlin. https://redmine.stoutner.com/issues/989
Combine drawable files. https://redmine.stoutner.com/issues/794
Update the URL in the copyright header. https://redmine.stoutner.com/issues/796
Add a View Source activity. https://redmine.stoutner.com/issues/64
Create a floating action button for creating bookmark folders. https://redmine.stoutner.com/issues/197.
Create a dark theme for `BookMarksActivity` and `BookmarksDatabaseViewActivity`.
Updates about_licenses, adding the full text of the Apache License 2.0 and the 3-Clause BSD License.
Add the ability to create and edit bookmark folders.
Add the ability to select all bookmarks.