Standardize the app bar icon size. https://redmine.stoutner.com/issues/877
Combine drawable files. https://redmine.stoutner.com/issues/794
Create a dark theme for `SettingsActivity`.
Create a dark theme for `GuideActivity`.
Updates about_licenses, adding the full text of the Apache License 2.0 and the 3-Clause BSD License.
Add icons to `DomainSettingsFragment`.
Remove lint errors in non-java files. Fix download dialog when download size is unknown. Only apply default font zoom on initial load.
Partial additional action button icons implementation.