Lots of changes during the weekend:

	- New style management code:  All styles are now managed by
	  regions on a sheet (the default region, is attached to the
	  complete sheet).

	- Styles can now be partial: Only some parts of the style
	  might be valid (this is very important).

	- Insert column/Insert row/Shift rows has been fixed and
	  it now computes properly the dependencies on any
	  data change.

	- Linking/unlinking formulas now takes care also of
	  adding/removing the dependencies of the cell.

Miguel.