Replace airline with lightline (much better perfomance)

sources_non_forked/lightline.vim/autoload/lightline/tab.vim

@@ -0,0 +1,33 @@
+" =============================================================================
+" Filename: autoload/lightline/tab.vim
+" Author: itchyny
+" License: MIT License
+" Last Change: 2016/05/07 22:31:02.
+" =============================================================================
+
+let s:save_cpo = &cpo
+set cpo&vim
+
+function! lightline#tab#filename(n) abort
+  let buflist = tabpagebuflist(a:n)
+  let winnr = tabpagewinnr(a:n)
+  let _ = expand('#'.buflist[winnr - 1].':t')
+  return _ !=# '' ? _ : '[No Name]'
+endfunction
+
+function! lightline#tab#modified(n) abort
+  let winnr = tabpagewinnr(a:n)
+  return gettabwinvar(a:n, winnr, '&modified') ? '+' : gettabwinvar(a:n, winnr, '&modifiable') ? '' : '-'
+endfunction
+
+function! lightline#tab#readonly(n) abort
+  let winnr = tabpagewinnr(a:n)
+  return gettabwinvar(a:n, winnr, '&readonly') ? 'RO' : ''
+endfunction
+
+function! lightline#tab#tabnum(n) abort
+  return a:n
+endfunction
+
+let &cpo = s:save_cpo
+unlet s:save_cpo