adapted to current spec: Locations
- Locations must not be inline anymore
- Meetings have their own locality properties now (making Papers the only objects that link to an Location)
adapted to current spec: Document renamed to File
testdata/file added some recommended properties
testserver: overwrite default logging method
the default logging method just prints messages to stdout, but we want to collect them for verification in crawler test functions
test_crawler: replaced fix_url
testdata/system: fix small error
crawler: fix python 3 compatibility
test_crawler: added whitelist test