Add support for virtualenvwrapper if its present
diff --git a/plugins/virtualenv.plugin.bash b/plugins/virtualenv.plugin.bash
new file mode 100644
index 0000000..a0e7b3f
--- /dev/null
+++ b/plugins/virtualenv.plugin.bash
@@ -0,0 +1,5 @@
+#!/bin/bash
+
+# make sure virtualenvwrapper is enabled if availalbe
+[[ `which virtualenvwrapper.sh` ]] && . virtualenvwrapper.sh
+