indexlib: add page_number to IndexItem
indexlib: add page_number to IndexItem

The multi-page renderer needs to know on which page each IndexItem has
been found. Therefore, we introduce a new page_number field in the
IndexItem class. This field remains to None for the single page
renderers, and is used to store an integer by the multi-page renderer.

Signed-off-by: Thomas Petazzoni <a5d87d2bd7c424ee5cbdb4e978635bf653d5a005@enix.org>

maposmatic/ocitysmap,dittaeva/ocitysmap,maposmatic/ocitysmap,dittaeva/ocitysmap,maposmatic/ocitysmap