changes for compatibility with elasticsearch 0.90.0.Beta1 (move to lucene 4 and some minor method renames)

see also http://lucene.apache.org/core/4_2_0/MIGRATE.html
Merge pull request #2 from q42jaap/master

changes for compatibility with elasticsearch 0.90.0.Beta1 (move to lucene 4.1 and some minor method renames)