The FeatureOracle provides tri-state feature lookup functionality for bare JIDs. It returns Yes if a feature is supported by all resources of the bare JID, Maybe if some support it, and No if none of the resources support it. If passed a full JID, it returns the specific features supported by that end-point. Sending a file to a bare JID, will send a file to the resource of the bare JID with the highest availability by presence, show status and priority and which supports the features required for a Jingle file-transfer. Test-Information: Added unit test verifying new behavior. All tests pass on OS X 10.11.6. Added new unit tests for FeatureOracle. Manually verified that the roster and chat window both use the same mechanism to detect support for file-transfers. Manually verified that file-transfers via the contact list goes to already bound full JIDs if there is an existing ChatController. Change-Id: I0175ac42ecb73f1d54f9c96ffbba773eb5e24296