Creates renderMinified response method to minify HTML output.

 Resolves #23.
`renderMinified` must be the same path that you use in the required module `../server`; Check the line below (#45) that try to mock the authentication module.
The correct line should be: `'./app/config/middlewares/render-minified': {renderMinified: renderMinifiedSpy}`
And you should set `var renderMinifiedSpy = sinon.spy();` before `srv_requires` declaration