Utilities for hierarchy creation and comparision plus fixes

• Add HierarchyDiff class with compare_hierarchies method to compare two hierarchies in CX2 format, and output
  a hierarchy with robustness score of each system.

• Add version bounds for required packages.

• Add convert_hierarchical_network_to_hcx (utility function that aids convertion of a hierarchical network in CX2 to
  HCX) and add_hcx_members_annotation (adds 'HCX::members' attribute to nodes) to hcx_utils

• Fixes in IF and APMS tools