Merge Homework 6.2 and 6.3

[mariussterling]

I did not change the output of the computational result (except cosmetics), simply the plotting function, such that it now plots the relative abs. error of the price (|'Bermudan option priced with integration method' / 'Analytical solution' - 1|). But I kept the previous integrated sensitivity analysis plots, accessible by an argument, see the titles of the plots.