doc/user: remove redundant encoder plugin settings
doc/user: add links
doc/user: enable docbook-xslt option "use.id.as.filename"
doc/protocol: enable docbook-xslt option "use.id.as.filename"
doc/user: add sections for bit-perfect playback and DSD
input/async: add method IsPaused()
input/nfs: auto-reconnect if failed while paused
output/pulse: simplify _wait_for_operation()

Eliminate the duplicate pa_operation_get_state() call.
doc/user: require bit-perfect playback for DoP
Merge remote-tracking branch 'upstream/master'