Drawing for HaplotypeGraph

[shz9]

The draw method of the HaplotypeGraph class is currently broken.
We need a new method that properly represents the haplotypes and the individuals to whom those haplotypes belong. Issues with current representation:

• Currently, nodes are laid out to minimize crossings, which leads to separating haplotypes from the same individual. Therefore, we need to figure out a layout that doesn't do that.
• The method should accommodate various types of HaplotypeGraphs (e.g. autosomal, mitochondrial, etc.).
• Ideally, this method should be moved to the Drawing script.