[Docs] Copyediting

[Docs] Copyediting

 * Add meta author, description and generator tags
 * Add Hugo version beside the logo and in the footer
 * Suggest the user to run `go get -u -v` to update dependencies
 * Requires Go 1.3+ rather than Go 1.1+
 * Improve rendering/formatting in some places
 * Add trailing slash to URLs where appropriate
 * GitHub redirects all http requests to https, update accordingly