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.
Another quick, but easy, grammatical mistake, for proper grouping place the comma after "C++" rather than after "Java." Thus we have "This algorithm is used as the default random number generator in Java and C++, and is still used in a wide variety of situations."