build-sys: Fix a variable value check

Change-Id: Ie39c9c335baf70d5a6c40fa4b6845ff78e2812ec
tunnel-sink-new: Limit the maximum latency to 200 ms

The default maximum latency is 10 seconds, which is not good,
especially since the tunnel sink doesn't support rewinding. Due to the
lack of rewinding, e.g. volume changes take a long time with large
latencies.

Change-Id: I13753d30a17598ebc9e6a3eda3db4096ff6fcf4e
tunnel-sink-new: Fix requested latency check

This fixes a bug in latency configuration. The wrong type in the cast
caused UINT64_MAX being not treated as special, so the configured
latency was set to UINT64_MAX usecs, which of course is absurdly huge
latency.

Change-Id: Iec239e7970944ed920837580a09bfe76a2ae2bfd
module: Add PA_CORE_HOOK_MODULE_UNLOAD

Change-Id: I20a6bdd2f367a332554d86219de0ea22e08d82d9
tunnel-manager: New module for managing tunnels to remote servers

Currently the module only supports creating tunnels for all devices in
the system instance, which is useful for implementing the "cascaded
setup" (user instances running on top of the system instance). In the
future it should be configurable which remote server(s) and which
devices to use.

Change-Id: I3d41936451572b6341cfb9717e07b355d8449490
packaging: Install module-tunnel-manager.so

Change-Id: I0502677165496449db85569f985de1a317f781b1
systemd: Disable TCP socket activation for user instances

The TCP port can be listened by only one process, so if the system
instance listens it, then user instances can't listen. Or if there
are multiple users, only one can listen.

Since systemd uses an "all or nothing" approach, the unix socket
activation doesn't work either when the TCP socket fails. It's not
terribly important to have TCP socket activation (at least at this
point), so let's just drop it from user instances.

Change-Id: I6258ee9c7a5ae7de4dcee209440de2df7a779e1d
Add configuration for the "cascaded setup"

If cascaded.pa is installed, then hardware should be managed by the
system instance, and user instances should use the hardware via the
system instance.

Change-Id: I6879bbcb50e131941c75b8c91a11e098d07428e5
Add systemd service and socket files for the system mode

Change-Id: If3783b3a86108dd968911613f5f63693cb5161c6
packaging: Add the pulseaudio-cascaded-setup package

Change-Id: I1a1504ac2496af127557c5d45f64fef4c284cdc6
system.pa: Load module-switch-on-port-available

Change-Id: I5067ad68f3c8bade0fbef3efc1e37b364b55a11e