Merge pull request #333 from HDFGroup/lkurz-robots-frontmatter

Update robots.txt frontmatter

robots.txt

@@ -1,4 +1,10 @@
-robots.txt generated by www.seoptimer.com
+---
+layout: none
+---
+User-agent: *
+Sitemap: {{ site.url }}/sitemap.xml
+Sitemap: {{ site.url }}/doxygen-content-sitemap.xml
+
 User-agent: *
 Disallow: 
 Disallow: /cgi-bin/
@@ -9,5 +15,3 @@ Disallow: /ftp/newsletters/
 Disallow: /ftp/HDF5/documentation/
 Disallow: /ftp/HDF5/examples/
 Disallow: /ftp/HDF5/projects/
-Sitemap: https://support.hdfgroup.org/sitemap.xml
-Sitemap: https://support.hdfgroup.org/doxygen-content-sitemap.xml