When the count is changed or pausing finishes, I trigger this callback
to notify the UI. I also added in a line to enable pausing any time the
count is incremented.
Signed-off-by: Anna Schumaker <schumaker.anna@gmail.com>
I implemented an entire Gtk::TreeModel in this commit, plus some minor
supporting code in the library to look up playlist entries by index.
Signed-off-by: Anna Schumaker <schumaker.anna@gmail.com>