Routing

A suggestion for having custom routing in PHP for better URLs. For example, `https://lmms.io/documentation/?page=1.0:Getting_Started` becomes `https://lmms.io/documentation/1.0:Getting_Started`. More changes like this are possible, for the LSP for example, also rendering pages using a template engine like [Twig](http://twig.sensiolabs.org/) will be feasible.

This is only for sharing the proposed changes, please don't merge, as some changes in the nginx configuration would be needed.