Make cf_reference_item public, so it can be used in

	Make cf_reference_item public, so it can be used in
	%{config:...}

	Made internal configuration code reference sub-sections by
	instances, too.  This allows ${foo.bar[baz]} references.

	Added internal "confdir" directive in cf_file_read, which
	adds "confdir" as the FIRST configuration item in "main".
	This allows the rest of the configuration files and directives
	to be tied to ${confdir}, meaning the server can be built
	with one target directory, but still run out of another