insert first snippet by default instead of cancelling

snipmate_vim_plugin_tweak.vim

" Apply this edit to plugin/snipMate.vim

fun s:ChooseSnippet(scope, trigger)
  " Original last line (which cancels on enter) commented out
  "return num == -1 ? '' : s:multi_snips[a:scope][a:trigger][num][1]

  " Two lines added to choose first snippet if none are selected
  let snip_to_return = num == -1 ? 0 : num
  return s:multi_snips[a:scope][a:trigger][snip_to_return][1]
endf