Parole reports "Gstreamer backend error, could not initialise supporting library" because "gstreamer1.0-pulseaudio" is missing.

[Impact]
* Some users are unable to use parole because the pulseaudio backend cannot be opened.
* The upload fixes this issue by adding gstreamer1.0-pulseaudio to recommends. Most (all?) ubuntu distributions use pulseaudio as a backend, so this can help future users as well.

[Test Case]
* On a clean system, run parole and try to open a video file.
* The error "Gstreamer backend error, could not initialise supporting library" may be displayed, preventing the user from viewing their media.

[Regression Potential]
* This upload adds a single gstreamer1.0 backend to recommends, so the risk of regression is slim to none.

[Original Bug Details]
I use newly installed Xubuntu 14.04. When I try to open a video file, Parole pops up a dialog box, say that "Gstreamer backend error, could not initialise supporting library".

This is the output from the terminal, with gst debug level = 2:

somporn@somporn-P4M900T-M2:~$ parole --gst-debug-level=2 SomeVideo.webm
Cannot connect to server socket err = No such file or directory
Cannot connect to server request channel
jack server is not running or cannot be started
0:00:00.756042853 10578 0x7fc9ae233700 WARN jackclient gstjackaudioclient.c:359:gst_jack_audio_get_connection: could not create connection
0:00:00.756305455 10578 0x7fc9ae233700 WARN jacksink gstjackaudiosink.c:359:gst_jack_ring_buffer_open_device:<audio-actual-sink-jackaudio> error: Jack server not found
0:00:00.756380823 10578 0x7fc9ae233700 WARN jacksink gstjackaudiosink.c:359:gst_jack_ring_buffer_open_device:<audio-actual-sink-jackaudio> error: Cannot connect to the Jack server (status 17)
0:00:00.758265641 10578 0x7fc9ae233700 WARN default oss4-property-probe.c:376:gst_oss4_property_probe_get_values:<audio-actual-sink-oss4> Can't open file descriptor to probe available devices: No such file or directory
0:00:00.758452068 10578 0x7fc9ae233700 WARN oss4sink oss4-sink.c:516:gst_oss4_sink_open:<audio-actual-sink-oss4> error: Could not open audio device for playback.
0:00:00.758515932 10578 0x7fc9ae233700 WARN oss4sink oss4-sink.c:516:gst_oss4_sink_open:<audio-actual-sink-oss4> error: system error: No such file or directory
0:00:00.759750439 10578 0x7fc9ae233700 WARN oss gstosssink.c:399:gst_oss_sink_open:<audio-actual-sink-oss> error: Could not open audio device for playback.
0:00:00.759963397 10578 0x7fc9ae233700 WARN oss gstosssink.c:399:gst_oss_sink_open:<audio-actual-sink-oss> error: system error: No such file or directory
0:00:00.760421367 10578 0x7fc9ae233700 WARN autodetect gstautoaudiosink.c:373:gst_auto_audio_sink_detect:<audio> error: Failed to find a supported audio sink
0:00:00.760646274 10578 0x7fc9ae233700 ERROR playbin gstplaybin2.c:5136:activate_group:<player> failed to activate sinks

You'll notice that it doesn't try to use pulseaudio, cause gst to failed to find a supported audio sink.

The workaround is to install "gstreamer1.0-pulseaudio" manually.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: parole 0.6.1-0ubuntu3
ProcVersionSignature: Ubuntu 3.13.0-24.46-generic 3.13.9
Uname: Linux 3.13.0-24-generic x86_64
ApportVersion: 2.14.1-0ubuntu3
Architecture: amd64
CurrentDesktop: XFCE
Date: Sat Apr 19 19:57:41 2014
InstallationDate: Installed on 2014-04-19 (0 days ago)
InstallationMedia: Xubuntu 14.04 LTS "Trusty Tahr" - Release amd64 (20140416.2)
SourcePackage: parole
UpgradeStatus: No upgrade log present (probably fresh install)