Make DocBlock parser use PhpDocumentor's DocBlock component

Use DocBlock parser from phpDocumentor to ensure we always parse according to latest PhpDoc standards. All previous DocBlock parser tests are passing on phpDocumentor DocBlock parser as well.

Side benefit:
New DocBlock parser is converting class/interface/trait names to FQCN format and that allows to detect exception classes in `@throw` and `@throws` tags and make them clickable in generated documentation.

Parsing performance change: does it 1 second faster (was 34 seconds for me) on Symfony codebase.

Closes #101