Ignore unknown style id hash.
Added a new method add_print_title to Worksheet that can be used to
specify rows and columns that are duplicated on each printed page.
Added support for preserving vba and controls in a loaded worksheet.
This is controlled using an additional boolean parameter 'keep_vba' to
load_worksheet. keep_vba defaults to false but if set to true then any
vba or Xactive or Form controls will be preserved and should still
be there and working when the sheet is saved.
Merged main branch
Merged branches
Updated default style for case when color_index not in excel sheet.
Fix header loading.
Load row dimensions.
Removed unused ifilter import.
Added support for RibbonX in customUI/customUI.xml
Fix wrong XML attribute.
Merged in parent
Merged in ctgPi/openpyxl (pull request #3)

Fix wrong XML attribute.
Fix merge.  Allow Named Range to contain full-column ranges (sheet!$A:$B).
Fix merge (indentation of patternFill).
Merged in parent
Merged with parent
Added a test for the completeness of the output file when keep_vba=True.
Added additional VBA test.
Cleaned whitespace.