Skip all triples with blank nodes in subject or object position

Before, only triples with blank nodes in subject positions were
skipped. When we actually reference blank nodes in the object
position and load the triples into a Jena model, the blank nodes in
the object position can't be resolved, since the triples with blank
nodes in the subject position were skipped.

This change fixes this by skipping all triples with blank nodes.

To handle blank nodes, we could take a similar approach as for our
other resolutions (e.g. resolve creator literals from GND triples).
Surround objects with whitespace when writing N-Triples

Jena handled the triples without whitespace just fine, but
whitespace between predicate and object is required by the spec
(see http://www.w3.org/TR/rdf-testcases/#ntriples). Whitespace
between object and dot is optional, but added for clarity.
Update and expand scripts

Fix classpath issue caused by missing 'export', use 'enrich' HDFS
directory in initial conversion, add updates script to illustrate
our current usage (combine 'enrich' and 'hbzlod' for initial
conversion, combine 'enrich' with 'update' for updates conversion).
Tweak search result presentation

- Wrap RDF in `pre` tags
- Turn document ID headers into links
- Use tab groups for different serializations
Add additional route for simple queries with defaults

Allows queries like `GET /id/9783458171652`, `GET /author/Abramson`
(index defaults to `lobid-index`, result defaults to `page`, can
both be specified additionally, see sample on index page).
Change default result format from `page` to `full`
Add content negotiation for API calls with 'full' result format

- Return different RDF serializations depending on 'Accept' header
- Add tests with 'Accept' headers for different RDF serializations
- Update index page with basic documentation on content negotiation
Add Scala project nature for IDE support in routes and templates
Update to Play 2.1.1 (config files, content negotiation API)
Automatically insert supported accept headers into index page
Make API tests self-contained and add them to CI

- Create a local, in-memory elasticsearch node in the tests
- Index some sample data in the local node
- Run tests against a local mock server using the local node
- Add test execution to the Travis CI config (`play test`)
Make HDFS to ES indexing tests self-containd and add them to CI

- Upload test data to a local in-memory Hadoop MiniDFSCluster
- Index test data in a local in-memory elasticsearch node
- Update config files (JUnit, Maven, and Travis setup)
Basic setup for HTML output with RDFa (tags for each document type)
Set up HTML+RDFa template for lobid-resources, filled from JSON-LD
HTML+RDFa template for lobid-organisations using current index data
Set up HTML+RDFa template for GND data, filled from JSON-LD
Extract reusable template blocks into a separate RDFa template tag
Split up index and result pages into two templates (index, docs)
Add content negotiation for HTML with RDFa output
Add clickable sample requests returning HTML+RDFa ('page' format)