New methods for Genome class

Changed returned Result in CheckGenome to avoid displaying each error.
Now it's a cell holding the result + error text (if any).

Added a mutation method and parameters to the Genome object. The Mutate
method allows mutation of several sequences at once and has several
mutation options.

Added a crossover method with 3 types of crossovers: 1-point, 2-point or
uniform (n-point).

Added a RandSeq method which can generate batches of random sequences.

All the new methods check the sequence after creating/modifying it.