[mms] Fix getString() in certain use cases.

I'll admit the getString() usage is a bit wonky, but it is an
established API call and, thus, the proper way to return strings from
the object based on lengths.
Revert "Add Horde_Stream::read"

This reverts commit 86ac160f9919a26b7483309594723497587cafb3.

Conflicts:
	framework/Stream/lib/Horde/Stream.php
Revert "CHANGES"

This reverts commit 56a3eb6f20d2c9a3ea81bd8abf7bb7650e719bea.

Conflicts:
	framework/Stream/package.xml
Horde_Stream#read() doesn't exist