Gst.NotInitialized exception on startup
When starting mopidy built from git develop branch, starting mopidy failed with `gi.overrides.Gst.NotInitialized: Please call Gst.init(argv) before using GStreamer`. It seems the call to `Gst.is_initialized()` before `Gst.init()` in `mopidy/internal/gi.py` is causing it. When I changed it to call `Gst.init([])` without checking if it's already initialized, the problem went away. `Gst.init()` also needed an argv-array as argument in my version, so I also passed an empty list as argument. Don't know if these changes are compatible with earlier versions of gst-python.

I'm on Archlinux, running gstreamer 1.6.3 and gst-python 1.6.2.

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diff --git a/mopidy/internal/gi.py b/mopidy/internal/gi.py
index 1407a657..7fa51f09 100644
--- a/mopidy/internal/gi.py
+++ b/mopidy/internal/gi.py
@@ -7,8 +7,7 @@ import textwrap
 try:
     import gi
     gi.require_version('Gst', '1.0')
-    gi.require_version('GstPbutils', '1.0')
-    from gi.repository import GLib, GObject, Gst, GstPbutils
+    from gi.repository import GLib, GObject, Gst
 except ImportError:
     print(textwrap.dedent("""
         ERROR: A GObject Python package was not found.
@@ -22,7 +21,9 @@ except ImportError:
     """))
     raise
 else:
-    Gst.is_initialized() or Gst.init()
+    Gst.init([])
+    gi.require_version('GstPbutils', '1.0')
+    from gi.repository import GstPbutils
 
 
 REQUIRED_GST_VERSION = (1, 2, 3)
['mopidy/internal/gi.py']