started Fries Museum
added fields (todo test)
fix fries museum
Implement an extractor for wikimedia commons (for tropen museum)
fries museum: production place singleton
Working proof of concept for tropenmuseum.
docs: fix centraal museum utrecht, add friesmuseum
Try to infer image size from meta items if possible.
friesmuseum: static xml and image host
Finish up stuff for the Tropen museum
Resolved the following issues with the WikimediaCommonsExtractor:

- Removed unnecessary references to OAI
- Simplefied overall structure
- Don't request a thumbnail since we are currently only after the largest available version of the file
- Don't request pervious versions of a file, we are only interested in the most recent version
- There's a bug in the Commons API that sometimes leads to returning invalid XML when requesting the 'meta' option (we now skip 'meta')
Changes to TropenMuseumItem:

- Removed unnecessary namespaces
- Don't store date if not present
- Replaced references to Tropen Museum website with Wikipedia URL's
  because the Tropen Museum URL construction was not reliable
- Descriptions are now also extracted with the help of BeautifulSoup
- Removed unused imports
Updated Tropenmuseum docs
Merge branch 'breyten-tropenmuseum'

Conflicts:
	docs/user/datasets.rst
	ocd_backend/sources.json
Fix malformed table in docs
Don't print extracted date
Use 'image/jpeg' content type for '.jpg' media
Default operator should be AND. Fixes #53
Merge branch 'friesmuseum' of https://github.com/bennokr/open-cultuur-data into bennokr-friesmuseum

Conflicts:
	ocd_backend/sources.json
Created sepearte extractor to extract static files