Reordering &rtp to have ~/.vim at first place.

This seems like a brute force method but it does the job on Mac OS X (I
suspect on all *nix systems).

Could close #244.

autoload/vundle/config.vim

@@ -81,6 +81,8 @@ func! s:rtp_add_a()
   let appends = join(paths, '/after,').'/after'
   exec 'set rtp^='.fnameescape(prepends)
   exec 'set rtp+='.fnameescape(appends)
+  set rtp-=~/.vim
+  set rtp^=~/.vim
 endf
 
 func! s:rtp_rm(dir) abort