0.5 release

[houfu]

This pull request introduces several enhancements and refactorings to the redlines project, including new features, code restructuring, and dependency updates.

New Features:

• Added a new command simple_text to redlines/cli.py to compare strings and output the redline in the terminal. (redlines/cli.py) Closes #37
• Introduced support for BBCode in the markdown styles for redlines. (redlines/redlines.py) [1] [2] Closes #39
• Added tests for the new BBCode markdown style. (tests/test_redline.py)

Code Restructuring:

• Extracted text processing logic into a new redlines/processor.py file and created a WholeDocumentProcessor class to handle the redline generation. (redlines/processor.py, redlines/redlines.py) [1] [2] [3] [4]

Dependency Updates:

• Updated pyproject.toml to include project metadata and dependencies for both runtime and development. (pyproject.toml)

Documentation:

• Improved the docstring for the text function in redlines/cli.py to provide a clearer description of its functionality. (redlines/cli.py)