SEO

Add meta tags:
https://support.google.com/webmasters/answer/79812?hl=en

DONE Add breadcrumbs:
https://developers.google.com/search/docs/data-types/breadcrumbs

DONE Create sitemap:
 - USE XML, and specified time / date modified
   https://developers.google.com/search/docs/guides/create-URLs
   https://support.google.com/webmasters/answer/183668?hl=en&ref_topic=4581190

Create list of functions?
 - https://developers.google.com/search/docs/guides/mark-up-listings

Add searchbox directly?
 - https://developers.google.com/search/docs/guides/enhance-site#add-a-sitelinks-searchbox-for-your-site

DONE Mark with structured data?
 - https://schema.org/SoftwareSourceCode

Mark with facebook opengraph?
 - http://ogp.me/

Search examples:
  https://github.com/google/search-samples/