v2.3.0

Now also including versions without an accented bar! They're still fairly WIP, and some parts of the design may change (e.g. I may decide to not accent all the buttons, and just have them be text coloured) and is still a little flawed, e.g. the icons for rating a track are barely visible.
This release also fixes a couple of icons that weren't properly themed, and the "unknown artist" and "no abum artwork" images.