by default don't use Werror
allow standalone table import from xlsx

This allows to use the table import for small parts of an import process
without the need to bring in the whole orcus in one big step.
Fix the control file to adjust for a bug fix in ixion.

Ixion's name resolver would previously print all range references as
relative i.e. without the $ signs.  That was fixed and we need to change
the control file to reflect it.
Add new files to slickedit projects & fix header guard.
Add new schema types for pivot cache and pivot table relations.
Set up paths for pivot cache and table parts in the OPC handler.

They are empty for now.
Set up skeleton pivot table xml parts handler.
Add skeleton handler for pivot cache definition parts.

One thing to note is that the same pivot cache definition part is
referenced multiple times: once from the workbook.xml and twice or
more times from the pivotTable#.xml parts.  One way to handle this is
to have the OPC code to keep track of which parts have already been
read, and skip any attempts to read the same part twice.
Store handled part paths to avoid reading the same part twice.

And follow the relations of pivot cache and pivot table parts.
No output when the debug flag is not set.
Add skeleton code for pivot cache record parts.
Parse the pivot cache definition parts for real.

For now, I'll dump the data to stdout.  Later I'll work on designing
a public interface for this.
Add test xlsx document that has pivot tables in it.
Comment unused method arguments.
Parse pivot cache record parts & dump content to stdout for now.
Class descriptions.
Parse the attributes of pivotTableDefinition in the pivot table part.
Parse pivotTable[n].xml parts fully.
<pivotField> element has 'dataField' boolean attribute.
Some comments.  Pivot table structure is really complex...

And reading the spec adds more confusion.