Pelican-extended-sitemap

* fixed date format in sitemap
* changed xml stylesheet link for this package to PyPI

* adjusted documentation

* adjusted documentation

* adjusted documentation

* initial release covering index, articles, pages, categories, tags and author pages


[14]: https://github.com/dArignac/pelican-extended-sitemap/issues/14
[11]: https://github.com/dArignac/pelican-extended-sitemap/issues/11
[10]: https://github.com/dArignac/pelican-extended-sitemap/issues/10
[8]: https://github.com/dArignac/pelican-extended-sitemap/pull/8
[5]: https://github.com/dArignac/pelican-extended-sitemap/issues/5