Revert "table alignment: break out of loop when separator found"

This reverts commit 23d273d547, which
fixes #655.

Description of fixed problem:
1. When looping through rows, if a separator was found, all subsequent
   rows would not get an assigned alignment.
2. This breaks `s:get_aligned_rows` because it calls `s:fmt_sep` and
   `s:fmt_row`, both of which expect `aligns` to have a value for every
   row number.

autoload/vimwiki/tbl.vim

@@ -278,8 +278,7 @@ endfunction
 function! s:get_cell_aligns(lnum)
   let aligns = {}
   for [lnum, row] in s:get_rows(a:lnum)
-  let found_separator = s:is_separator(row)
-    if found_separator
+    if s:is_separator(row)
       let cells = vimwiki#tbl#get_cells(row)
       for idx in range(len(cells))
         let cell = cells[idx]
@@ -291,15 +290,15 @@ function! s:get_cell_aligns(lnum)
           let aligns[idx] = 'left'
         endif
       endfor
-      return aligns
+    else
+      let cells = vimwiki#tbl#get_cells(row)
+      for idx in range(len(cells))
+        if !has_key(aligns, idx)
+          let aligns[idx] = 'left'
+        endif
+      endfor
     endif
   endfor
-  if !found_separator
-    let cells = vimwiki#tbl#get_cells(row)
-    for idx in range(len(cells))
-      let aligns[idx] = 'left'
-    endfor
-  endif
   return aligns
 endfunction