OpenRefine/OpenRefine — pull request #867 by abhillman (2014-04-12 23:50:15+00:00)
Title: Fix when exporting to excel files

When exporting to excel, there cannot be more than 255 columns.
If there are more columns than that, we write "ERROR: TOO MANY
COLUMNS" to the 255th column. Formerly, OpenRefine reported
a 500 Server error. Addresses issue #834, https://github.com/OpenRefine/OpenRefine/issues/834.