[#33] & [#34] : JSON serialization configuration. Pretty printing only in test/dev environment.

http://docs.spring.io/spring-boot/docs/current/reference/html/howto-spring-mvc.html suggests that Views should not be used for JSON serialization of objects:
>Note that ViewResolvers are mainly used in UI applications, rather than REST-style services (a View is not used to render a @ResponseBody).

When I debugged it, ViewResolver method indeed was not used by Spring Boot at all.

So I found a better way of JSON configuration:
http://springinpractice.com/2013/11/01/how-to-pretty-print-your-json-with-spring-and-jackson

Also introduced pretty printing configuration mechanism which takes into account active profile.
Pretty printing is only done in test/dev environment.
I am only not sure that it (`MappingJackson2HttpMessageConverter`) should (has to) be exposed as @Bean - it is only used here locally.