row_finder_by_color(): finds row based on anchor cell, using known column and fill color
find_fill_color(): finds fill color of specified cell in excel sheet, to help use row_finder_by_color()
row_finder(): finds row number based on an "anchor" cell of known column and pattern.
as_numeric_smart(): as.numeric(), but correctly handles cases of numbers with commas in them, numbers ending in %s.
copy_columns(): copies specified sets of columns from start_row to end_row from one file into another, with highlighting of cells copied and cells with changed values
implant_df() and copy_section() to copy sections of excel sheets
addition of clip_to_vec() to make coding easier
addition of validate_*() for input validation
TODO: