Support rowspans and colspans in grid tables (#8202)

* Add tests for zero-width and fullwidth chars in grid tables

* T.P.Parsing: simplify `gridTableWith'`, `gridTableWith` [API Change]
  The functions `gridTableWith` and `gridTableWith'` no longer takes a
  boolean argument that toggles whether a table head should be parsed:
  both, tables with heads and without heads, are always accepted now.

* Support colspans, rowspans, and multirow headers in grid tables.

  Grid tables in Markdown, reStructuredText, and Org can now contain cells
  spanning over multiple columns and/or multiple rows; table headers
  containing multiple rows are supported as well.

Note: the markdown writer does not yet support these more complex grid
table features.

1 files changed, 26 insertions, 0 deletions

diff --git a/test/markdown-reader-more.txt b/test/markdown-reader-more.txt
index c6f313b20..8d2bed5ef 100644
--- a/test/markdown-reader-more.txt
+++ b/test/markdown-reader-more.txt
@@ -286,6 +286,32 @@ Empty cells
 |   |   |
 +---+---+
 
+
+Table with cells spanning multiple rows or columns:
+
++---------------------+----------+
+| Property            | Earth    |
++=============+=======+==========+
+|             | min   | -89.2 °C |
+| Temperature +-------+----------+
+| 1961-1990   | mean  | 14 °C    |
+|             +-------+----------+
+|             | min   | 56.7 °C  |
++-------------+-------+----------+
+
+Table with complex header:
+
++---------------------+-----------------------+
+| Location            | Temperature 1961-1990 |
+|                     | in degree Celsius     |
+|                     +-------+-------+-------+
+|                     | min   | mean  | max   |
++=====================+=======+=======+=======+
+| Antarctica          | -89.2 | N/A   | 19.8  |
++---------------------+-------+-------+-------+
+| Earth               | -89.2 | 14    | 56.7  |
++---------------------+-------+-------+-------+
+
 ## Entities in links and titles
 
 [link](/ürl "öö!")