added git ignore

.gitignore

+# See http://help.github.com/ignore-files/ for more about ignoring files.
+#
+# If you find yourself ignoring temporary files generated by your text editor
+# or operating system, you probably want to add a global ignore instead:
+#   git config --global core.excludesfile ~/.gitignore_global
+
+/tmp
+*/**/*un~
+*un~
+.DS_Store
+*/**/.DS_Store
+