Specific Markdown processor to use within Nitweb

Property definitions

nitc :: api_docdown $ NitwebConfig :: md_processor
	# Specific Markdown processor to use within Nitweb
	var md_processor: MarkdownProcessor is lazy do
		var parser = new CommandParser(model, mainmodule, modelbuilder, catalog)
		var proc = new CmdMarkdownProcessor(parser)
		proc.decorator = new CmdDecorator(model)
		return proc
	end
src/doc/api/api_docdown.nit:22,2--28,4