Improve .gitignore

Change-Id: I4e9fd33f199b90a4b7c8cf8b9fcc6d18c532842d
Reviewed-by: Debao Zhang <dbzhang800@gmail.com>
Reviewed-by: Jonas Rabbe <jonas.rabbe@gmail.com>

.gitignore

@@ -17,6 +17,22 @@ qrc_*.cpp
 config.log
 *.pro.user
 tmp
+
+#
+# Includes
+#
 include
 src/multimedia/qtmultimediaversion.h
 src/multimediawidgets/qtmultimediawidgetsversion.h
+
+#
+# Snippets
+#
+*.so
+*.so.*
+
+#
+# Tests
+#
+tst_*
+!tst_*.cpp