0.4.0

• Create ComparableGroup class for unordered Factor collections
• Create FactorSequence class for ordered Factor collections
• Eliminate Analogy class, moving its methods to FactorGroup and FactorSequence
• Add Factor.consistent_with method to search for available context avoiding contradiction
• Add "or" operator for FactorGroup
• Integrate Legislice API client for retrieving text from US Constitution and US Code
• Remove functions for loading legislation text from XML files. Use API client instead.
• Delete classes for accessing XML legislation files: Code, Regime, and Jurisdiction