sync event extension docs with it's 1.6.0 release

git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@329987 c90b9560-bf6c-de11-be94-00142212c4b1
Del: deprecated event methods

git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@329988 c90b9560-bf6c-de11-be94-00142212c4b1
Fix: references to renamed methods EventBuffer::remove and EventBuffer::removeBuffer

git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@329989 c90b9560-bf6c-de11-be94-00142212c4b1