merged changes from Trunk up to r37094 from addressbook, calendar, infolog, phpgwapi, egw-pear and resources (only CalDAV/CardDAV related stuff of cause)
- unfortunatly Netdrive uses no User-Agent header, so we can only detect it on the absense of one
- we use now rawurlencode with replacing / and : afterwards, instead of the minimal version, which is the default