Minor doc block improvements

http://ch1.php.net/manual/de/exception.construct.php
Second parameter gets only passed by. Exception constructor uses an int for the second parameter,not a string.

Replaced text by docblock @see
http://www.phpdoc.org/docs/latest/for-users/phpdoc/tags/see.html
Merge pull request #1402 from ravage84/patch-2

Minor doc block improvements