Increased maximum scan interval. Closes #22.
New log file viewer tab in settings.

 Adapted from Artwork Downloader by Martijn Kaijser.
Loading settings is now done in an external module
Moving various functions to a utilities module
Removed internal loading of settings and linked to the new module
Write list of cleaned videos to a logfile
Custom window to display log because of layout issues
Moved log related methods to their own class
Handle LogViewer arguments better
More logging while performing file operations
Remove unused error handling method
Reuse existing window when clearing or trimming
Better consistency with Dutch translation
Fixed trimming duplicating the lines to keep
Fixed button and caption positioning in log viewer
Fixed imports
Update addon.xml with new requirements
Fixed some constants' encodings
Optimized imports (again)
Coloring of buttons and background