ifad/clammit

CLAMMIT:

 - the ClamInterceptor class should be in its own source file
 - main.go:378, broken_err can be overridden if more than one
   file in the request errs out
 - document program architecture (interceptor, forwarder, etc)
 - not really like passing the http response around, because
   this way http response codes are scattered around the code

GO-CLAMD:

 - fix memory leak https://github.com/ifad/clammit/pull/22