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