UltiSnip <tab> everything

.vimrc

" UtilSnips
" The <tab> key works as follow
" - if there is popup: <c-n> (next popup item)
" - if there is something behind cursor
"   - try expand snippet
"   - if can't expand, try jump
"   - finally try <c-n> (key word completion)
" The <s-tab>:
" - if there is popup: <c-p> (previous popup item)
" - try jump back
" - finally try <c-p> (key word completion)

if !has('python')
  let did_UltiSnips_vim=1
endif

let g:UltiSnipsEditSplit='horizontal'
let g:UltiSnipsExpandTrigger='<c-j>'
let g:UltiSnipsExpandJumpForwardTrigger='<c-j>'
let g:UltiSnipsExpandJumpBackwardTigger='<c-k>'
let g:UltiSnipsExpandJumpBackwardTigger='<s-tab>'
let g:UltiSnipsListSnippets='<c-l>'

if has('python')
python << EOF
import vim, os, sys
sys.path.append(os.path.expanduser('~/.vim/bundle/vim-ultisnips/plugin'))
from UltiSnips import SnippetManager

def handle_tab(self):
  rv = self._try_expand()
  if not rv:
    rv = self._jump()
    if not rv:
      return '\<c-n>'
  return ''

SnippetManager.handle_tab = handle_tab

def handle_shift_tab(self):
  if not self._jump(True):
    return '\<c-p>'
  return ''

SnippetManager.handle_shift_tab = handle_shift_tab
EOF

function! UltiSnips_HandleTab()
  if pumvisible()
    return "\<c-n>"
  endif
  let col = col('.') - 1
  if !col || getline('.')[col - 1] !~ '\k'
    return "\<tab>"
  else
    exec g:_uspy "vim.command('return \"%s\"' % UltiSnips_Manager.handle_tab())"
  endif
endfunction

function! UltiSnips_HandleShiftTab()
  if pumvisible()
    return "\<c-p>"
  endif
  exec g:_uspy "vim.command('return \"%s\"' % UltiSnips_Manager.handle_shift_tab())"
endfunction

inoremap <tab> <c-r>=UltiSnips_HandleTab()<cr>
inoremap <s-tab> <c-r>=UltiSnips_HandleShiftTab()<cr>
endif