Complete implementation of add_events for incremental updates

[korentomas]

Description

Hi @glandfried! How have you been doing? I am going to try using TTT in practice. This PR completes the implementation of the add_events method in Python, enabling incremental updates to History objects without recomputing from scratch.

Motivation

As discussed in PR #10, the ability to add events incrementally is essential. The previous attempt relied on the trueskill() method which "only serves at the first time". This implementation follows the pattern from the Julia version which handles message passing correctly.

Changes

• Fixed logic bug in Batch.add_events() (was checking if a in b.skills, should be if a not in b.skills)
• Implemented complete History.add_events() with proper message passing
• Added test coverage
• Created example documentation showing "real-world" usage

Testing

All new functionality is covered by tests. The implementation follows the same logic as the working Julia version.

Co-authored by @apiss2

[glandfried]

Nice to see you here! I’ll review the code this week. If you’re interested, I can show you a new version of the code that it’s simpler, cleaner, and includes new capabilities for handling discrete observables (such as goals).

[glandfried]

We have a new version v2.0.0 in:

• branch https://github.com/glandfried/TrueSkillThroughTime.py/tree/upgrade/score-points
  cc @korentomas

[glandfried]

Pull Request V2.0.0.