Update Blackjack Lab

Updated the solutions. Removed randomness tests. Combined Mersenne twister with LCG. Cleared up the Blackjack section to be more comprehensive and understandable for students.
Just a quick comment: on the pdf, something seems to be wrong with the reference, it says \ref{sweeps} corresponds to problem 6 rather than 4, as it should. Check your labels to make sure they are clear.