Optionally use ZIP64 compression. Bump to 1.3.0.

Added right-to-left worksheet capability. Bump to 1.2.0.

Added XlsxNumberFormat.Text (a.k.a. @).

Removed need for CreateStyle and added transparent style deduplication.

Bump to 0.0.9.

Removed FontScheme property from stylesheets to enable Excel properly…

… identify font faces, thanks @improtag

Polished API a bit, added documentation.

Fixed fallback of null strings on empty cells.

Fallback on empty cell if string value is null.

Added Write() method for empty cells.