improve the requirement checks
improve the requirement checks

- reordered the requirements to make more sense
- improve wording, e.g. a test message like "OK  Your project might not work properly ..." is very confusing when the requirement is fulfilled.
- made some tests conditional so that a requirement is only checked when necessary (otherwise it's misleading). E.g. only check Suhosin config, when Suhosin is installed.
- fixed compatibility with PHP 5.2
HeahDude/SensioDistributionBundle,HeahDude/SensioDistributionBundle,sensiolabs/SensioDistributionBundle,sensiolabs/SensioDistributionBundle