examples: Added identity example

Created a simple BaseTransform element (identity)

https://bugzilla.gnome.org/show_bug.cgi?id=772853

examples/plugins/python/identity.py

@@ -0,0 +1,42 @@
+#!/usr/bin/env python
+# -*- Mode: Python -*-
+# vi:si:et:sw=4:sts=4:ts=4
+
+# identity.py
+# 2016 Marianna S. Buschle <msb@qtec.com>
+#
+# Simple identity element in python
+#
+# You can run the example from the source doing from gst-python/:
+#
+#  $ export GST_PLUGIN_PATH=$GST_PLUGIN_PATH:$PWD/plugin:$PWD/examples/plugins
+#  $ GST_DEBUG=python:4 gst-launch-1.0 fakesrc num-buffers=10 ! identity_py ! fakesink
+
+import gi
+gi.require_version('GstBase', '1.0')
+
+from gi.repository import Gst, GObject, GstBase
+Gst.init(None)
+
+#
+# Simple Identity element created entirely in python
+#
+class Identity(GstBase.BaseTransform):
+    __gstmetadata__ = ('Identity Python','Transform', \
+                      'Simple identity element written in python', 'Marianna S. Buschle')
+
+    __gsttemplates__ = (Gst.PadTemplate.new("src",
+                                           Gst.PadDirection.SRC,
+                                           Gst.PadPresence.ALWAYS,
+                                           Gst.Caps.new_any()),
+                       Gst.PadTemplate.new("sink",
+                                           Gst.PadDirection.SINK,
+                                           Gst.PadPresence.ALWAYS,
+                                           Gst.Caps.new_any()))
+
+    def do_transform_ip(self, buffer):
+        Gst.info("timestamp(buffer):%s" % (Gst.TIME_ARGS(buffer.pts)))
+        return Gst.FlowReturn.OK
+
+GObject.type_register(Identity)
+__gstelementfactory__ = ("identity_py", Gst.Rank.NONE, Identity)