Mutable implementation of solution encodings

[abeham]

Vectorized solution encodings (BinaryVector, Permutation, ...) are currently derived from ValueTypeArray<T>. This is inefficient as additional data is stored (elementNames list) and a lot of changed events are fired. Thus using the indexers may be quite inefficient.

It would be preferable to have solutions as immutable data structures and thus avoid the change handling. In addition, only the necessary data should be stored.