Supports the yajl version 2

Initially the code was made to support the yajl version 1. The
version 2 is now the default option in most of Linux distributions.
Adds support to JSON parser in the nginx module

Building with --enable-standalone-module was failing due
the lack of the reference to the msc_json.c file inside the
standalone/Makefile.am. This patch also place the dependency
of the yajl to the nginx module config script.