close quickfix window when last win open

" Raimondi's solution
" 17 Aug 2010

function! KillQF()
  if bufwinnr(bufnr('%')) == 1 && winnr('$') == 1 && getbufvar('%', '&buftype') == 'quickfix'
    exit
  endif
endfunction

augroup goodQF
  au!
  au WinEnter * silent call KillQF()
augroup END