[libsigcplusplus] Update tests/.gitignore

[Murray Cumming <murrayc src gnome org>]

commit e533da86ecb50c991e4c6962d55c34f62dd6a0d3
Author: Murray Cumming <murrayc murrayc com>
Date:   Wed Apr 20 11:46:44 2016 +0200

    Update tests/.gitignore

 tests/.gitignore |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/tests/.gitignore b/tests/.gitignore
index d59cabc..f3b439f 100644
--- a/tests/.gitignore
+++ b/tests/.gitignore
@@ -39,3 +39,5 @@
 /test_tuple_start
 /test_tuple_transform_each
 /test_visit_each
+/test_visit_each_trackable
+/benchmark