enh(exporter): add filters and callbacks, tidy up options

Add a headerFilter so that you can work with i18n.  Add
a fieldCallback so that you can decode coded data as part
of the export.

Rename some options to be better aligned with current usage.

Update unit tests and tutorials.
Merge pull request #1862 from PaulL1/exporter_pdf_translate

enh(exporter): add filters and callbacks, tidy up options