Grouping of formula cells during undo.
Grouping of formula cells during undo.

Change-Id: I57693eee34a073cd3f39fdd4f5a74eafb12c9dc7

JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core