Make it easier to customize configuration of default middleware

[dlongley]

It should be easier to configure default middleware for specific endpoints -- or to just skip all the defaults and setup your own custom middleware for a specific route. For example, there are places where we want to change the JSON body parser limit.

[davidlehn]

Perhaps related: #8

[gannan08]

This may help the cause. expressjs/body-parser#245 (comment)

[dlongley]

Closing as #62 has mostly addressed this and provided a pattern to adopt for any other default middleware where this kind of feature is needed.