README update

Introduction to Aura, links, case fixes, etc.
`The [Aura System](http://auraphp.com/framework) is a full-stack framework built around these Aura library packages.` this is still not true. It is v1 . In this we are talking about v2 projects like https://github.com/auraphp/Aura.Web_Project , https://github.com/auraphp/Aura.Cli_Project , https://github.com/auraphp/Aura.Framework_Project . So this section needs more edit .