Just include the modules necessary in the Request object to implement
the things we need.  This should make it easier to build delegate
request objects because the API is smaller

Now that we have encoding strategies, we can just walk the params hash
once to encode as HWIA, and remove nils.

we'll refactor deep munge mostly out of existence shortly

This should have been done along with 8f8ccb99

deep_munge solves CVE-2013-0155 security vulnerability, but its
behaviour is definately confuisng. This commit adds logging to deep_munge.
It logs keys for which values were set to nil.

Also mentions in guides were added.

ActionDispatch::Request#deep_munge was introduced as a private method,
but was turned into a public one for the use of
ActionDispatch::ParamsParser.

I have extracted it into ActionDispatch::Request::Utils, so it does not
get mixed up with the Request public methods.