Update README.md with CI/CD Information and Feature Status

[Advaitgaur004]

This pull request brings several updates to README.md to better reflect the current status and development practices of the cTensor project.

Key Changes Proposed:

• Added "Continuous Integration" Section:

  • Details the newly implemented GitHub Actions workflows for:
  • Automated building and testing across multiple platforms (Linux, macOS, Windows) via run-ctests.yml.
  • Verification of test results using check_all_results.py.
  • Operator test coverage checks via check-operator-test-coverage.yml to ensure all tensor operators have corresponding tests.
  • This section highlights the project's commitment to code quality and automated checks.

• Updated "Testing the Library" Section:

  • Ensured testing instructions are accurate, including the correct name for the test executable (e.g., cten_tests or cten_tests.exe as built by CMake).

• Refreshed "Features" List:

  • Reviewed and updated the "Currently Implemented" and "Development Roadmap" sections.
  • Moved recently implemented features from the roadmap to the implemented list.
  • Ensured the list of tensor operations and neural network components accurately reflects the library's current capabilities.

• General Enhancements:

  • Minor improvements to clarity, formatting, and accuracy throughout the document.

These updates aim to provide developers and users with a more comprehensive and up-to-date overview of the cTensor library, its features, and its development infrastructure.