Feature: #68184 - Paths to typo3/cms package and document root can be specified in composer.json

Description

With the new composer installer it is possible to specify the path of the document root and also the path of the typo3/cms package.

It can be specified in the extra section of your composer root package like that:

{
	"repositories": [
		{ "type": "composer", "url": "http://composer.typo3.org/" }
	],
	"name": "typo3/cms-base-distribution",
	"description" : "TYPO3 CMS Base Distribution",
	"license": "GPL-2.0+",
	"config": {
		"vendor-dir": "Packages/Libraries",
		"bin-dir": "bin"
	},
	"require": {
		"typo3/cms": "dev-master"
	},
	"require-dev": {
		"mikey179/vfsStream": "1.3.*@dev",
		"phpunit/phpunit": "~4.4.0",
		"twbs/bootstrap": "3.3.*",
		"fortawesome/font-awesome": "4.2.*"
	},
	"extra": {
		"typo3/cms": {
			"cms-package-dir": "{$vendor-dir}/typo3/cms",
			"web-dir": "web"
		}
	}
}

Impact

When specifying the configuration like mentioned above, the directory structure of a composer install will change.