don't remove the installed.txt file
Merge pull request #451 from WouterSioen/patch-6

don't remove the installed.txt file
* Filesystem: add filesystem component to composer
* Filesystem: register filesystem as a service
Merge branch 'filesystem' of https://github.com/guytarded/forkcms into filesystem

Conflicts:
	app/config/config.yml
	composer.json
add filesystem to composer and register as a service