Removed README from DAVClient.
Adjusted namespaces and implemented DAV client from fruux/sabre-dab.
RequestBuilder concept + CardDAV AddressBookMultiGetRequestBuilder example.
Fixed up README.md.
Merge pull request #1 from stevelacey/carddav-request-builder

RequestBuilder concept + CardDAV AddressBookMultiGet support
Switched to sabre/dav dev-master.