[dev] remote calendar authentication

[Tom Evans]

Kronolith users can subscribe to remote calendars in ICS format. I would
like to add the ability to connect to remote calendars that require a
username/password. A quick scan of the Kronolith code indicates that
this would be fairly straightforward, since the PEAR HTTP_Request
supports basic authentication. However, I would need to add a couple of
parameters to some methods in the Kronolith class (e.g.
Kronolith::getRemoteCalendar and Kronolith::listRemoteEvents) to pass in
the optional credentials.

Before we write a patch, I wanted to check in and avoid BC problems with
this sort of change. Are these methods part of the formal calendar API? 
If so, can I add method parameters without breaking  backward compatibility?

Also, I would like to encrypt the credentials so they will not be
visible as clear text in the horde_prefs table. Any suggestions? Perhaps
there is an approach that could also be used to conceal the fetch mail
preferences in IMP?

Tom