QA: direct access from commandline to AppLayer API

QA: direct access from commandline to AppLayer API

This patch introduces a new set of commandline options meant for
assisting in fuzz testing the app layer implementations.

Per protocol, 2 commandline options are added:

--afl-http-request=<filename>
--afl-http=<filename>

In the former case, the contents of the file are passed directly to
the HTTP parser as request data.

In the latter case, the data is devided between request and responses.
First 64 bytes are request, then next 64 are response, next 64 are
request, etc, etc.