fixed security_advisory check to work with refactored ZendDiagnostics
Added config for php_version
Docfix: Notation seems to be yml, but in text called xml
Fixed config and added documentation
Fixed typo in Configuration
Added check for php_flag
Some better configuration options
Updated readme with actual configuration
Merge remote-tracking branch 'origin/master' into check_config_for_php_flag

Conflicts:
	DependencyInjection/LiipMonitorExtension.php
Fixed typo
Merge pull request #56 from frne/master

Enable PhpVersion Check
Merge remote-tracking branch 'upstream/master' into check_config_for_php_flag
Removed debug and added some documentation
Merge pull request #57 from frne/check_config_for_php_flag

Add check-config for php_flag
Added readable_directory
Added class_exists check
Added stream_wrapper_exists check
Added cpu_performance check
require symfony 2.3+, added composer suggests
tightened up configuration (closes #51)