support for DAV:status code and DAV:location, plus sync-collection fix

[dankarp]

• expose DavResource's optional DAV:status value

  DAV resources may contain a DAV:status instead of a DAV:propstat. We parse these optional status lines and expose the status code (or 200 when absent) via DavResource.getStatusCode.

  A small code reorg moves the propstat properties as final members of an inner class.

• complete DAV:response by including DAV:location element

  RFC 4918 includes a "location" element in a DAV:response:

       <!ELEMENT response (href, ((href*, status)|(propstat+)),
                           error?, responsedescription? , location?) >

       <!ELEMENT location (href)>

Add support for an optional <DAV:location> element in a
<DAV:response> by updating webdav.xsd and generating new
Response and Location JAXB model classes.  (We also update the
ObjectFactory, which is not currently auto-generated.)

Note that the location value is not currently exposed by
DavResource.

• minor fixes for the sync-collection report

  Fix DAV:sync-collection in webdav.xsd by straightening out the property order, the allowable DAV:sync-limit values, and the syntax of the DAV:limit element. Update the JAXB model classes and our SyncCollectionReport object as appopriate.

[dkocher]

Can you please rebase with the master branch which will also make the tests green.

[dkocher]

Replaced by pull request #241.