Merge pull request #33 from wgorder/master

Labels with spaces or special characters should be escaped with backticks
fix bug for support for standard Ops.EXIST to translate to cypher has
fix bug when lucene start queries have spaces
Add support for the UNION clause
Merge pull request #35 from wouterv/fix-exists-bug

fix bug for support for standard Ops.EXIST to translate to cypher has function
Merge pull request #36 from wouterv/fix-lucene-space-bug

fix bug when lucene start queries have spaces
Merge pull request #37 from wgorder/feat/union

Add support for the UNION clause
updated to 2.0.4
Fixed: ExecuteWithParams.parameters(Map) incorrect use of local variable #38
Update to QueryDSL 3.4.2