SourceViewVC doesn't deal well with moved/deleted files

[bright-tools]

The "file" and "diff" links provided when using the SourceViewVC plug-in will not work correctly in the case that the target is in an SVN repo and is subsequently moved or deleted.

This seems relatively easy to overcome using the pathrev parameter to ViewVC in order to ensure that ViewVC is using not only the specified version of the files but also the appropriate version of the path information.

I will submit a pull request for this.