WEBS assignment

WEBS assignment things...

Questions 1&2: see prac 5

Question 3: see prac 7
Additional requirements for question 3: can implement 0 or 1 or 2 of those...
(means best to do both)

Question 4: means proper error messages

Question 5: the question is clear enough...

Deadline: shifted to 8 Jan, after demo(no need to upload on 4 Jan)