Restores future support for annotations

In #89 the regex to parse tags was to strict. The first character after a tag
had to be a single string. Annotations typically start with a parentheses. Only character not
allowed after a tag is a [.

src/DocBlock/StandardTagFactory.php

@@ -113,6 +113,12 @@ final class StandardTagFactory implements TagFactory
 
         list($tagName, $tagBody) = $this->extractTagParts($tagLine);
 
+        if ($tagBody[0] === '[') {
+            throw new \InvalidArgumentException(
+                'The tag "' . $tagLine . '" does not seem to be wellformed, please check it for errors'
+            );
+        }
+
         return $this->createTag($tagBody, $tagName, $context);
     }
 
@@ -161,7 +167,7 @@ final class StandardTagFactory implements TagFactory
     private function extractTagParts($tagLine)
     {
         $matches = array();
-        if (! preg_match('/^@(' . self::REGEX_TAGNAME . ')(?:\s+([^\s].*)|$)/us', $tagLine, $matches)) {
+        if (! preg_match('/^@(' . self::REGEX_TAGNAME . ')(?:\s*([^\s].*)|$)/us', $tagLine, $matches)) {
             throw new \InvalidArgumentException(
                 'The tag "' . $tagLine . '" does not seem to be wellformed, please check it for errors'
             );