Add integration tests

Closes #27.
Update to Lucene 4.8.1 / Elasticsearch 1.2.0

Related to #24.
Beidermorse encoder does not support "replace" option

Beidermorse encoder does not support "replace" option: only new tokens will be returned.
One of the backfires is that highlighting will not work.
This is actually because Lucene's beidermorse filter does not support this option.
Please consider to update documentation by specifying which encore support `"replace : false"` option.

Closes #22.