Multiline @return statements were stripped from their newlines and indent

@return statements (and effectively others) were stripped from their newlines
and indentation. By tweaking the reflection a bit was this effect countered.

src/phpDocumentor/Reflection/DocBlock.php

@@ -199,8 +199,6 @@ class DocBlock implements \Reflector
                 continue;
             }
 
-            $tag_line = ltrim($tag_line);
-
             if (isset($tag_line[0]) && ($tag_line[0] === '@')) {
                 $result[] = $tag_line;
             } else {
@@ -325,7 +323,7 @@ class DocBlock implements \Reflector
             $ignore_keywords = array(
                 'string', 'int', 'integer', 'bool', 'boolean', 'float', 'double',
                 'object', 'mixed', 'array', 'resource', 'void', 'null',
-                'callback', 'false', 'true'
+                'callback', 'false', 'true', 'self', '$this', 'callable'
             );
         }
 

src/phpDocumentor/Reflection/DocBlock/LongDescription.php

@@ -78,7 +78,7 @@ class LongDescription implements \Reflector
             );
         }
 
-        if (class_exists('\dflydev\markdown\MarkdownExtraParser')) {
+        if (class_exists('dflydev\markdown\MarkdownExtraParser')) {
             $md = new \dflydev\markdown\MarkdownExtraParser();
             $result = $md->transformMarkdown($result);
         }

src/phpDocumentor/Reflection/DocBlock/Tag/ReturnTag.php

@@ -34,7 +34,8 @@ class ReturnTag extends ParamTag
     {
         $this->tag = $type;
         $this->content = $content;
-        $content = preg_split('/\s+/u', $content);
+
+        $content = preg_split('/[\ \t]+/u', $content, 2);
 
         // any output is considered a type
         $this->type = array_shift($content);