[dev] rest driver

[Roel Gloudemans]

In Horde bugs 1500 and 917 I see that a rest driver is implemented and 
that Chuck is even using it. So I tought let's give it a try.

I tried the URL 
https://[servername]/horde/rpc.php?restCall=calendar.exportCalendar&restContentType=text/calendar&calendarName=r.gloudemans&contentType=text/calendar
(HTTP authentication is on, so rpc.php should be able to authenticate)

but I get an Internal Server error in return. Nothing is logged in the 
horde log, only in the apache log.

What am I missing here?

Cheers,
Roel.