implemented loading of a portal
implemented caching mechanism for portal configs
defined portal xsd file
added language to portal class
finished entity classes for portal
implemented the xml import
updated test and portal collection to complete entity classes
implemented caching and portalmanger
implemented new find methods
check if xml files are valid, skip the invalid ones, and log a warning for them
corrected phpunit.xml
added service definition
corrected tests
Merge branch 'develop' of https://github.com/sulu-cmf/sulu into feature/portal

Conflicts:
	composer.json
	src/Sulu/Bundle/CoreBundle/DependencyInjection/SuluCoreExtension.php
code review & cleanup
code review & cleanup
Merge branch 'develop' of https://github.com/sulu-cmf/sulu into feature/portal
Merge branch 'feature/portal' into develop