Log Message:
py-openpyxl: updated to 2.4.9

2.4.9 (2017-10-19)
Bugfixes
* 809 Incomplete documentation of copy_worksheet method
* 811 Scoped definedNames not removed when worksheet is deleted
* 824 Raise an exception if a chart is used in multiple sheets
* 842 Non-ASCII table column headings cause an exception in Python 2
* 846 Conditional formats not supported in write-only mode
* 849 Conditional formats with no sqref cause an exception
* 859 Headers that start with a number conflict with font size
* 902 TableStyleElements don’t always have a condtional format
* 908 Read-only mode sometimes returns too many cells
Pull requests
* 179 Cells kept in a set
* 180 Support for Workbook protection
* 182 Read support for page breaks
* 183 Improve documentation of copy_worksheet method
* 198 Fix