Merge pull request #406 from jeremyclement/master

Resolve error "E518: Unknown option: undofile" for vim < 7.3

git/gitconfig

@@ -1,4 +1,4 @@
-# set your user tokens as enivornment variables, such as ~/.secrets
+# set your user tokens as environment variables, such as ~/.secrets
 # See the README for examples.
 [color]
   ui = true

vimrc

@@ -49,10 +49,11 @@ set nowb
 " ================ Persistent Undo ==================
 " Keep undo history across sessions, by storing in file.
 " Only works all the time.
-
-silent !mkdir ~/.vim/backups > /dev/null 2>&1
-set undodir=~/.vim/backups
-set undofile
+if has('persistent_undo')
+  silent !mkdir ~/.vim/backups > /dev/null 2>&1
+  set undodir=~/.vim/backups
+  set undofile
+endif
 
 " ================ Indentation ======================