formatting commit
addressing testcase failures
adding one more scenario to case
adding one more scenario to case
Adding update and unmerge functions for merge cell handling
adding one more case to testcase
adding testcases to base code
adding testcase for import/export
adding documentation to some of the PUB function
fixing warnings and test warnings
adding merge cell part cell update restriction to public sytle set fns
addressing reviwers comment : Changed Mergedcell structure and its side effercts
reverting it back to non pub.
renaming update_merge_cells to just merge_cells in model
renaming *unmerge_merged_cell* to *unmerge_cells*
addressing other reviewer's comment + cosmetica naming adjustments
cosmetic changes
