Catch the exception thrown if a DocBlock cannot be read.

If
- The TagVisitor was active
- Any PhpDoc of a method contained "@" with a white space right after it.

An \InvalidArgumentException was thrown and not catched which broke the whole process of building dependencies.

The solution in this pull request tries to ignore the Exception as it is a problem of the phpDocumentor library. At the same time it logs the occurrence. This looks quite ugly if used in the command line though. Do you have any suggestions on that?