Replaced Martini with Negroni and Gorilla-mux

I like Martini and its approach with dependency injection, but it
is too much for WebAxs-Lite. What we need here is simple basis to
write Web application, that is familiar with Go-way.

See also this blog post about Martini and Negroni:
http://blog.codegangsta.io/blog/2014/05/19/my-thoughts-on-martini/