[cosmo-dev] icalendar url import support

[Randy Letness]

I just checked in support for importing an icalendar resource by url.  
Before, you could import an icalendar collection into cosmo by POSTing 
the icalendar contents.  Now you can simply POST to the same atom url, 
but instead of including the iclanedar in the request body, you can 
simply include the url to the icalendar resource.  So for example, the 
curl command to import a google calendar would be something like:

$ curl -u randy:pass -X POST --data 
'url=http://www.google.com/calendar/ical/developer-calendar%40google.com
/public/basic.ics' 
http://localhost:8080/chandler/atom/user/randy/import/devstuff

Now all we need is to add support in the webui for asking the user for 
an icalendar url and the webui can make the necessary atom request that 
results in that icalendar resource fetched and imported into a new 
collection.  This would be a great starter project for anyone wishing to 
jump into the webui (hint, hint).

-Randy