Version 3.23.0

• Refactored the Reader's code for easier maintenance and future improvements. This should have no effect in how it works compared to the previous version.
• Removed the old alternative PDF rendering library, pdfjs, as keeping it was adding unneeded complexity to the code and increasing the program's size.
• Fixed the default filter preview image used in the Preferences showing as broken due to a path change in a recent update.
• Fixed the context menu showing the rotation entry in the Reader even in page modes that don't allow it.