add bin to git ignore file

bin files are generated by Eclipse

Change-Id: I9e956eda00ab84c2f8bbafdbd793a163bb19f269
diff --git a/.gitignore b/.gitignore
index 6b468b6..49fb040 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,2 @@
 *.class
+bin