ZF-7897: Implement a ResponseDecorator for line indentation


Line indentation is currently done "by hand" for example in the console help system.

This could more easily be done with a ResponseDecorator that allows to specify the content option:

$response->appendContent("foo", array("indentation" => 8));

A patch for this decorator is appended.


Committed this to incubator in r18550 and r18551 (plus a previous faulty commit of the IndentionTest.php file in r18322)