More clean-ups

Better Cross-platform stuff

https://vimways.org/2018/from-vimrc-to-vim/

plugin/folders.vim

@@ -0,0 +1,30 @@
+" Stolen from maralla/dotvim
+function! s:EnsureExists(path) abort
+    let l:path = expand(a:path)
+    if !isdirectory(l:path)
+	try
+            call mkdir(l:path)
+        catch
+            echom "Could not create directory " . l:path
+	endtry
+    endif
+endfunction
+
+call s:EnsureExists(resolve($MYVIM . '/.cache'))
+
+" persistent undo
+if exists('+undofile')
+    let &undodir = resolve($MYVIM . '/.cache/undo')
+    set undofile
+    call s:EnsureExists(&undodir)
+endif
+
+" backups
+let &backupdir=resolve($MYVIM . '/.cache/backup')
+set backup
+call s:EnsureExists(&backupdir)
+
+" swap files
+let &directory=resolve($MYVIM . '/.cache/swap')
+set noswapfile
+call s:EnsureExists(&directory)