Improve playing a track with Google Earth

- directly send the play intent to Google Earth
- add a tour id to the feature to be played
- track the number of play using google analytics

SignalStrengthSamplerTest/project.properties

@@ -0,0 +1,11 @@
+# This file is automatically generated by Android Tools.
+# Do not modify this file -- YOUR CHANGES WILL BE ERASED!
+#
+# This file must be checked in Version Control Systems.
+#
+# To customize properties used by the Ant build system use,
+# "ant.properties", and override values to adapt the script to your
+# project structure.
+
+# Project target.
+target=android-15