Rudimentary bookmarking support for items.
Currently the locations of bookmarks are hardcoded to demonstrate the way things work, but I will be adding dbus calls soonish and integrating it more fully once I figure out this SQL thing.

To add a bookmark programatically, call ProgressSlider::instance()->addBookmark( uint seconds) or ProgressSlider::instance()->addBookmarks( QList<uint> seconds )Enjoy