Autoplay enhancement + new app icon

#58 - Autoplay enhancement

Many thanks to @LesterJitsi for requesting this enhancement!

Some users would prefer the app to quietly append files to the playlist when files are opened from Finder with the "Open With" action (equivalent to double-clicking files in Finder), without immediately starting playback of the opened files. So, a new option has been added under Preferences > Playback, to allow for this behavior.

NOTE - The default behavior will continue to be that the app begins playback of files opened with "Open With", but this can now be overriden.

#63 - New app icon

Many thanks to @VisualisationExpo for requesting this enhancement, and for providing the new icon!

Aural has a new app icon ... can't you see ;)