Refactor RobotLangVisitorUser to improve student ID extraction and clean up code

Q1/Artefacts/main.py

@@ -11,13 +11,9 @@ def main(argv):
         inpname = argv[1]
         inpstream = FileStream(inpname)
     lexer = RobotLangLexer(inpstream)
-    #Create a stream of tokens
     tokstream = CommonTokenStream(lexer)
-    #Parser produces the abstract syntax tree
     parser = RobotLangParser(tokstream)
-    #Start parsing from the top rule
     tree = parser.prog()
-    #execute script
     visitor = RobotLangVisitorUser()
     visitor.visit(tree)