Update to make more dynamic base on specified params in pyconfig

This is my first pull request so please be patient with me....

In the README.rst file I reordered the parameters to what I thought were logical groupings and added comment headers t clarify that the social media params were optional

In many of the templates I removed instances of SITEURL to make links relative. Having non-relative links makes it really difficult to serve pages on local serve for dev and troubleshooting. Everytime you click a link it attempts to take you to the production server.

In the footer I added IF blocks to all the icon/links. This way, if you don't specify a twitter account (for example) it doesn't add an icon with broken link.,

In base.html I added some meta name fields and a favicon field.