Vim gitignore

- why aren't these on by default dangit

.gitignore

@@ -5,3 +5,13 @@ build
 _site
 *.lock
 .sass-cache/
+# swap
+[._]*.s[a-w][a-z]
+[._]s[a-w][a-z]
+# session
+Session.vim
+# temporary
+.netrwhist
+*~
+# auto-generated tag files
+tags