Add docblock indent fixer

Ensure that docblocks for class methods and attributes are indented if present
EDIT: Ensure that any docblock uses the same indentation as the documented subject, regardless the type
In order to avoid duplicated array bound check, I would replace `$tokens[$next - 1]` with pass by copy of `$prevToken`, thus:

```
$prevToken = $tokens[$index - 1];
$indent = $this->calculateIndent($prevToken->getContent());
```