[mms] Failed recipients can now be determined via the Horde_Smtp_Exception_Recipients exception thrown when calling Horde_Smtp#send().
Catch bad recipients rejected by SMTP server and report to the user
update phpdoc
[mms] Add zlib driver and allow it to be considered a 'fast' compression driver (disabled by default).
Better abstraction of unit tests
Fix handling setlocale in unit tests

Need to put in setUp/tearDown, since we need to guarantee that the
locale will be reset after a failed test.