Change internal data format to `expanded` JSON-LD and update to ES 0.90.5

After upgrading to 0.90.5 (see #110), Elasticsearch complains about an inconsistency in our previous data format: with `comapct` JSON-LD, plain literals are serialized as strings, while e.g. literals with a language are serialized as an array of objects with `@value` and `@lang` keys. This results in different types for the same field (here: string and array).

Since Elasticsearch requires that a specific field has a consistent type, this commit changes the JSON-LD serialization to use the `expanded` format, which always encodes literals as object arrays. This also fixes the indexing issues we had before upgrading Elasticsearch (see #73). At the same time, the API still serves the `compact` format, so clients should not have to change their result processing logic.

As the format of the data created by the conversion from N-Triples to JSON-LD has changed, this commit increments the version number of lodmill-ld to 0.2.0-SNAPSHOT. It also deletes the Eclipse project config files in lodmill-ui, which have to be generated locally with `play eclipse`.

Deployed to staging, with all collections fully reindexed: http://staging.api.lobid.org/

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