ADD: Slider for volume control
ADD: write_files_to_db now updates the fields with data from the ID3 tags
ADD: Album cover now gets fetched on load
ADD: Add to queue now works (TODO - front end view)
ADD: New progress bar pointer
Same as last commit, but this time I remembered to stage the changes before commiting :/

ADD: Slider for volume control ADD: write_files_to_db now updates the fields with data from the ID3 tags ADD: Album cover now gets fetched on load ADD: Add to queue now works (TODO - front end view) ADD: New progress bar pointer