empty table cells become whitespace

[xfnw]

this causes tables with empty cells to become misaligned:

| column 1 | column 2 |
|          | column 2 |

gets parsed as

ORG_TABLE@0..47
  ORG_TABLE_STANDARD_ROW@0..24
    PIPE@0..1 "|"
    WHITESPACE@1..2 " "
    ORG_TABLE_CELL@2..10
      TEXT@2..10 "column 1"
    WHITESPACE@10..11 " "
    PIPE@11..12 "|"
    WHITESPACE@12..13 " "
    ORG_TABLE_CELL@13..21
      TEXT@13..21 "column 2"
    WHITESPACE@21..22 " "
    PIPE@22..23 "|"
    WHITESPACE@23..24 "\n"
  ORG_TABLE_STANDARD_ROW@24..47
    PIPE@24..25 "|"
    WHITESPACE@25..35 "          "
    PIPE@35..36 "|"
    WHITESPACE@36..37 " "
    ORG_TABLE_CELL@37..45
      TEXT@37..45 "column 2"
    WHITESPACE@45..46 " "
    PIPE@46..47 "|"

which renders as

column 1	column 2
column 2