Now it is possible to add <title> to each page at /2015/

Now it is possible to add <title> to each page at /2015/

To do this I put the LibrePlanet banner & sidebar in seperate files --
/server/2015/banner.html & /server/2015/sidebar.html

server/2015/boilerplate.html is the template for creating new pages at
/2015/

new file:   server/2015/banner.html
new file:   server/2015/boilerplate.html
modified:   server/2015/header.html
new file:   server/2015/sidebar.html

and added titles all HTML files.