Add single switch topology in mininet with two hosts. Useful to
demonstrate simple use cases like bridging between two hosts on
single switch.

Change-Id: I9499341facfed4e9da1d62cb17e20f539517f2cc
diff --git a/mininet/.gitignore b/mininet/.gitignore
new file mode 100644
index 0000000..e43b0f9
--- /dev/null
+++ b/mininet/.gitignore
@@ -0,0 +1 @@
+.DS_Store