Age of Middleware

This release introduces some changes, now we have three modes:

• --capture (to capture)
• --synthesize (all requests are sent to middleware and response is expected to come from middleware, requests are not allowed to propagate further)
• virtualize mode is the default one when you are not supplying mode flags

Biggest change is --middleware support, so now you can write middleware modules in any language, more on this stuff in readme.