Preserve newlines in docblock tags

This is especially important when using markdown.
Adding a blank line between text introduces a new paragraph.
Current implementation will result in all text staying in one paragraph
and also other elements like lists and code do not get recognized in
most cases.

Author: cebe

src/phpDocumentor/Reflection/DocBlock.php

@@ -209,20 +209,16 @@ protected function parseTags($tags)
                 );
             }
             foreach (explode("\n", $tags) as $tag_line) {
-                if (trim($tag_line) === '') {
-                    continue;
-                }
-
                 if (isset($tag_line[0]) && ($tag_line[0] === '@')) {
                     $result[] = $tag_line;
                 } else {
-                    $result[count($result) - 1] .= PHP_EOL . $tag_line;
+                    $result[count($result) - 1] .= "\n" . $tag_line;
                 }
             }
 
             // create proper Tag objects
             foreach ($result as $key => $tag_line) {
-                $result[$key] = Tag::createInstance($tag_line, $this);
+                $result[$key] = Tag::createInstance(trim($tag_line), $this);
             }
         }
 

tests/phpDocumentor/Reflection/DocBlockTest.php

@@ -14,6 +14,7 @@
 
 use phpDocumentor\Reflection\DocBlock\Context;
 use phpDocumentor\Reflection\DocBlock\Location;
+use phpDocumentor\Reflection\DocBlock\Tag\ReturnTag;
 
 /**
  * Test class for phpDocumentor\Reflection\DocBlock
@@ -272,7 +273,10 @@ public function testParseMultilineTagWithLineBreaks()
  */
 DOCBLOCK;
         $object = new DocBlock($fixture);
-        $this->assertCount(1, $object->getTags());
+        $this->assertCount(1, $tags = $object->getTags());
+	    /** @var ReturnTag $tag */
+	    $tag = reset($tags);
+	    $this->assertEquals("Content on\n    multiple lines.\n\n    One more, after the break.", $tag->getDescription());
     }
 
     /**