mpc: split up log levels
have sliders send updates immediately (like when using the mouse)
add helpful tip to people who find the console
mpc: merge old state with new state

Since mpd will, when it is stopped, return garbage or nothing at all for
many values, we need to filter/merge the results so the player looks sane.
update with full state now

Since mpc will pass us a fully merged state object, use that rather than
returning early assuming we have just a partial state.
show current volume/time in tooltips
tcp-client: update API URLs
tcp-client: allow caller to force pulling of more data

When we get a burst of data that fills up the buffer, we don't want to
delay 500 msecs for the buffer to refill.  So let the caller force a
fresh pull of data when it knows it is expecting more.
mpc: add playlist commands apis
mpc: properly handle responses that spread multiple buffers

When using commands like playlistinfo, the result is much larger than a
single buffer can handle.  So handle merging multiple buffers.
metadata: add a bit more info to the tab
mpc: handle ACK responses