Vtags on RObjects.  Max Score and Found Count on Search Method

There are two minor changes in this PR.

1.  New `Vtag` string on the `RObject` struct.  Gets set inside `setContent` when there aren't conflicts, just like the siblings get them.

2.  Changed the `Search` method signature to include the maximum score and the found count as return values.

The second item is a breaking API change.