#653 Collect items for quickfix from all buffers, and de-duplicate them. Set filename items in quickfix and loclist.

test/test_list_titles.vader

@@ -1,7 +1,9 @@
 Before:
   Save g:ale_set_loclist
   Save g:ale_set_quickfix
+  Save g:ale_buffer_info
 
+  let g:ale_buffer_info = {}
   let g:ale_set_loclist = 0
   let g:ale_set_quickfix = 0
 
@@ -43,6 +45,10 @@ Execute(The quickfix titles should be set appropriately):
 
   let g:ale_set_quickfix = 1
 
+  let g:ale_buffer_info[bufnr('')] = {
+  \ 'loclist': [{'bufnr': bufnr(''), 'lnum': 5, 'col': 5, 'text': 'x', 'type': 'E'}],
+  \}
+
   call ale#list#SetLists(bufnr(''), [
   \ {'bufnr': bufnr(''), 'lnum': 5, 'col': 5, 'text': 'x', 'type': 'E'},
   \])