Merge pull request #10 from stuartnelson3/patch-1

Add dragonfly to bsd build

isatty_bsd.go

@@ -1,4 +1,4 @@
-// +build darwin freebsd openbsd netbsd
+// +build darwin freebsd openbsd netbsd dragonfly
 // +build !appengine
 
 package isatty