[GA] Const correctness in Genotype

[Kri5t0fK]

Maybe also add get() for entire List _oddVertices?

SouvlakiSearch/SouvlakMVP/SouvlakMVP/Genotype.cs

Lines 25 to 35 in 1560793

	/// <summary>
	/// Genotype: a list of even number of "odd vertices".
	/// Odd vertices - vertices with odd number of neighbours.
	/// </summary>
	private readonly List<Graph.Vertex> _oddVertices;
	// Read-only Indexer for accesing the list
	public Graph.Vertex this[int i]
	{
	get { return this._oddVertices[i]; }
	}