ex12: typos in templates [minor]
ex12: implement Aufgabe 27. a), b) & c)
ex12: 27 a): predict() seems to be correct now [fix]
ex12: 27. d) predict with different sigma's and w's
ex12: plot test prediction as line instead of scatter
ex12: also plot the to-be-approximated function
ex12: reformat generate_data() slightly [minor]
ex12: test the covered range uniformly
ex12: add a workaround for bad behavior of generate_data()
ex12: choose different experiment parameters/constants