Modernize dependencies and CI/CD configuration

[Copilot]

Updates project dependencies and build tooling to work with modern Python versions (3.8-3.12) and current CI/CD systems.

Dependency Updates

pyproject.toml

• Migrated deprecated dev-dependencies to group.dev.dependencies
• Updated mypy: ^0.770 → ^1.0 (eliminates typed-ast incompatibility with Python 3.12)
• Updated pytest: ^5.4.1 → ^7.0
• Updated Sphinx ecosystem: ^3.0 → ^5.0 (latest compatible with Python 3.7+)
• Updated build backend: poetry.masonry.api → poetry.core.masonry.api

CI/CD Configuration

.travis.yml

• Updated distribution: xenial → jammy
• Expanded test matrix from Python 3.7 only to Python 3.8-3.12
• Migrated deprecated matrix syntax to jobs

.readthedocs.yml

• Updated to ReadTheDocs v2 format with explicit build configuration
• Updated Python version: 3.7 → 3.10 for documentation builds

All 25 existing tests pass. Type checking passes on all 48 modules.

Original prompt

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This section details on the original issue you should resolve

<issue_title>General cleanup and functionality check</issue_title>
<issue_description>Do a thorough cleanup and review</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes General cleanup and functionality check #34

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