Create custom ErrorMiddleware to support Rest

[smalot]

If you want to create a full Rest API, you need to override the ErrorMiddleware.
But this suppose to override the Application too because de ErrorMiddleware is added by default with too many code overriden due to "private" properties and methods.

It should be a good thing to restrict "private" properties and methods only when realy needed for security reasons or to forced code override in case of inheritance.

What's your point of view ?

[dkraczkowski]

Hello, there are already possibilities to achieve this functionality:

• Throw an exception that implements \Igni\Http\Exception\HttpException
• Add custom middleware by $app->use() or register module implementing \Igni\Http\MiddlewareProvider

I was also thinking about extending ErrorMiddleware and replacing it with one defined by user if it gets registered. But this will destroy modules that are implementing OnErrorListener interface.

[dkraczkowski]

I have also added PR with upgraded docs and improved current http exception handling #20