Fixes singletons and wip on HBase GroupBy

src/qir/ast/QIRNull.java

src/qir/ast/data/QIRLnil.java

src/qir/ast/data/QIRTnil.java

src/qir/ast/value/QIRBoolean.java

src/qir/driver/QIREvaluationVisitor.java

src/qir/driver/QIRGreedyReduceVisitor.java

src/qir/driver/hbase/HBaseDriver.java

src/qir/driver/hbase/QIRHBaseQueryVisitor.java

src/qir/driver/sql/QIRSQLStringVisitor.java

src/qir/driver/sql/SQLStringDriver.java

src/qir/util/QIRAny.java