**🚀 Features**
- Added support for PGFPlots with external data files.
- Introduced a new flag (`-k`) to retain LaTeX temporary files.
- Added support for grayscale output in rasterized mode.
- Introduced new flags `--save-tikz` and `--save-pdf` to save the TikZ and PDF files respectively; `--save-tex` now explicitly saves the full LaTeX document.
**🚨 Breaking Changes**
- Modified the save functionality: Options must now be passed in `TexDocument.run_latex(...)` as `TexDocument.save()` is no longer used.
- LaTeX rendering is now performed in the current folder, moving away from the use of a temporary directory (`tempdir`). This change facilitates access to external files for PGFPlots.