Note that the bar is disabled by default; you will need to enable it
on-demand somwhow.  One possible way is wrapping clementine in a script
like this:

    i3-msg bar mode dock clementine
    /usr/bin/clementine
    i3-msg bar mode invisible clementine

However, due to i3 limitation, this will not guarrantee that the main
bar will always end up in the very bottom of the screen.  To work around
this:

    i3-msg bar mode dock clementine
    sleep 1
    i3-msg bar mode invisible main
    sleep 1
    i3-msg bar mode dock main
    /usr/bin/clementine
    i3-msg bar mode invisible clementine

Or vote for i3 feature request to make this more predictable:

    https://github.com/i3/i3/issues/2797