ARIA issue with weekday and month elements

[oigewan]

Per https://www.w3.org/TR/wai-aria/roles#columnheader, the columnheader role should go on the equivalent of a <th> element and should be owned by something with the row role. Currently, the row is getting the columnheader role and the column headers don't get anything.

[oigewan]

Also, per https://www.w3.org/TR/wai-aria/roles#rowgroup rowgroup elements should be owned by something with a grid role.

[oigewan]

Question: In the next major version, should each month be a table? Makes layout easier...