vim: change the keymaps for moving buffers
vim: add keymaps in vimfiler buffer

* unmap    <buffer><Space>
* nnoremap <buffer>b           :<C-u>Unite -buffer-name=bookmark-vimfiler_history -default-action=cd bookmark vimfiler/history directory_mru<CR>
* nmap     <buffer>x           <Plug>(vimfiler_toggle_mark_current_line)
vim: Do no auto-wrap text using textwidth (does not apply to comments)
vim: add unite_vimfiler_directory_mru() function and assign <unite>d to it
vim: add new keymaps for moving up and down lines in unite buffer

* nmap <buffer>J 8gj
* nmap <buffer>K 8gk