This is a rewrite of the patch original developed by Craig Markwardt that fixes
timeout problems on iTunes 10.5+. It applies to forked-daapd GCD.
https://github.com/CBGoodBuddy/forked-daapd/commit/bd10978d5240bc22c03a6f3bd0492a6318b7d67d

Original commit message from Craig:

Details:

iTunes v10.5 clients changed how they responded to DAAP
protocol, and started disconnecting when the forked-daapd server
sent an empty "refresh" reply ("mupd" protocol).  This problem is
also coupled with session-timeout ("mstm" and "msal"); when these
server capabilities were enabled, iTunes 10.x clients did not poll
for updates and eventually disconnected.

I investigated DAAP network packets using Wireshark.  I found that
a true iTunes server sends a set of server capabilities in a specific
order, and order matters to the client.  When the correct order is used,
the client correctly polls for updates and does not disconnect.

This change:
  1. Send server capabilities in different order (daap_reply_server_info).
  2. Disables 5-minute update refresh.
  3. Disables 30-minute inactivity time-out.

Testing:
This server version successfully stayed connected to the
following clients:
  * iTunes 10.5.2
  * iTunes 10.4.2
  * iTunes 9.7.1
  * Rhythmbox 0.12.8
The clients stayed connected for at least several hours,
sometimes days, with activity or no activity.