- Better visitors

src/qir/ast/data/QIRLcons.java

src/qir/ast/data/QIRLnil.java

src/qir/ast/data/QIRTcons.java

src/qir/ast/data/QIRTnil.java

src/qir/driver/QIRSQLVisitor.java

src/qir/reduction/QIRGreedyReduceVisitor.java

src/qir/reduction/QIRReductor.java

src/qir/util/IQIRVisitor.java

src/qir/util/QIRPrintVisitor.java