AnnotationReader may incorrectly throw exceptions

_From @arnaud-lb on July 6, 2012 17:11_

The AnnotationReader pre-parses classes' doc block with a PreParser that doesn't have import (_use_) informations.

Due to this, it can happen that an annotation resolves to a wrong class.

The parser will then attempt to validate the class and fail (no @Annotation, cannot be used on classes, etc).

Here is a test case: https://github.com/doctrine/common/pull/161

The ArrayObject annotation is resolved as \ArrayObject, which is not a valid annotation. This results in the following exception:

```
Doctrine\Common\Annotations\AnnotationException: [Semantical Error] The class "ArrayObject" is not annotated with @Annotation. Are you sure this class can be used as annotation? If so, then you need to add @Annotation to the _class_ doc comment of "ArrayObject". If it is indeed no annotation, then you need to add @IgnoreAnnotation("ArrayObject") to the _class_ doc comment of class Doctrine\Tests\Common\Annotations\Issue159\ParseMe.
```

_Copied from original issue: doctrine/common#159_