mangle PATH_INFO before passing to subcontoller

Apart from that, this changeset also makes
* request.unmatched_path to be equal to PATH_INFO
* request and response are now defined per controller and are not shared between
  controllers
* fail two specs on how filters work...
add TODO to check if we mangle PATH_INFO correctly
fix specs on passing from inner controller filter

cause we have separated response/request objects in outer and inner controllers
and merging response objects override body we can't rely on response.body as an
indicator anymore
fix spec on reevaluation of filters

cause we don't share request/response between inner and outer controllers we
can't rely on passing state through setting response.status anymore
blocks do not need to have env as an arg
store unmangled PATH_INFO as scorched.path_info

this one can be useful for URL generation
fix PATH_INFO mangling for escaped values

this commit also removes the way to define subcontrollers for prefixes which
aren't complete slash-separated values
allow matches which do not end with slash
Merge pull request #16 from andreypopp/path_info_route

Routing via PATH_INFO