Implementation of boolean query parser (support of AND, OR and NOT).
Implementation of #339
Fix build issue

com.jaeksoft.searchlib.SearchLibException:
java.lang.NullPointerException
	at
com.jaeksoft.searchlib.request.SearchField.getTermQueryFilter(SearchField.java:200)
Merge pull request #342 from emmanuel-keller/master

Implemention of #339