ENG-224: added null/not null support to BMQL


git-svn-id: http://svn.terracotta.org/svn/ehcache@8110 b9324663-ca0f-0410-8574-be9b3887307d
Fixed javadoc for fields.


git-svn-id: http://svn.terracotta.org/svn/ehcache@8111 b9324663-ca0f-0410-8574-be9b3887307d