Add links to original page images

[tfmorris]

Without page images, there's no effective way for people to make corrections. Instead, they're just guessing.

[tfmorris]

This is related to #24 in that we might be able to use the info booklist.tsv which has the lsid if we can find a way to join to it.

The BL flickr page for 00000206 links to PDF http://access.bl.uk/item/pdf/lsidyv353f7be4 and catalog search.

We link to the catalog entry, but that one has no images and you have to jump through the "Related Resources" to find the record with the scan. The actual record connected to the PDF & image view links is this one

Possible ways forward:

• figure out how to join to booklist.tsv to get lsid
• scrape data from flickr API/web
• figure out how to access BL catalog programatically (API? Scrape)

[tfmorris]

I've generated crosswalk.tsv to map between print and digital versions and used it to create metadata/booklist-extended.tsv which contains all the related identifiers.

The links are:

• viewer - http://access.bl.uk/item/viewer/lsidyv353f7be4
• PDF - http://access.bl.uk/item/pdf/lsidyv353f7be4

The remaining piece of work is to add these to the README template.