added sitemap generation
fix missing slash in url in sitemap.tmpl
added lastmod for each url in sitemap.xml
Minor cleanups.
added robots.txt generation
add documentation
Bugfix to FMT refactor.
move sitemap to plugins
add sitemap.lisp in plugins
consistency
added doc for sitemap plugin
Merge pull request #33 from mrordinaire/sitemap

Added sitemap generation.
Minor cleanups to sitemap plugin.
README tweaks.
Minor cleanups to MAIN and LOAD-CONFIG.
Added first draft of theme documentation
Clean up theme docs and add overview.
Generalize DISCOVER for all content-types.
Factor render-index out of render-indices.
Update TODO. Minor sitemap plugin cleanup.