Optimization/Merging Progress

- Big rewrite on nearly everything
- Simple styles should now properly only reference a single styles
- Borders, etc, still need work on only referencing a single style
- Styling merging works for the most part, work is needed to make the border merging more complete
Version bump
MergedCells addition

- You can now merge a SimpleTypedList of cells (useful if you want to merge an entire row)