Added the following features as I regularly came across situations where they were required:
- Sheet Titles: Add title row before column headers
- Autofilter: enable autofilter on specified columns, starting from a specified row.
- Freeze Panes: freeze a span of rows from moving when scrolling the document
- Cross-compatible styling: fixed issues where widths and other styling weren't showing correctly on macOS versions of Excel, as well as some Linux spreadsheet viewers.