Migration to Lucene 4.9.0. Indexing, faceting and searching are working. Errors on CaseInsensitiveFieldComparatorSource.
Fix sort accross multiple languages.
Fix test failing due to change on indexing any field. This should not happen as the scale denominator 50000 should be part of the suggestion in the test. This need more investigation to identify why this is not part of the index terms.
Merge remote-tracking branch 'origin/stable-develop' into improvements/update-to-lucene-4.9.0

Conflicts:
	core/src/main/java/org/fao/geonet/kernel/search/LuceneSearcher.java
Cleaning.
Cleaning.
Cleaning.
Merge pull request #606 from fxprunayre/improvements/update-to-lucene-4.9.0

Update to lucene 4.9.0