finish visitor ExpExpressionFinder.
move method findStatementBaseCase
from PStmAssistantInterpreter class to StatementFinder class.
move the method findExpressionBaseCase
from PExpAssistantInterpreter class to ExpExpressionFinder class
new visitor SubExpressionLocator. Finished.
small changes needed.
create new visitor SingleBindValuesCollector.
Test entry fix.