Combine relative baseUri with relative path
<p>I'm looking for a clean way to combine a relative base Uri with another relative path. I've tried the following, but <code>Uri(Uri, string)</code> and <code>UriBuilder(Uri)</code> require absolute Uris (throwing InvalidOperationException: This operation is not supported for a relative URI).</p>

<pre><code>// where Settings.Default.ImagesPath is "~/path/to/images"
// attempt 1
_imagePath = new Uri(Settings.Default.ImagesPath, image);

// attempt 2
UriBuilder uriBuilder = new UriBuilder(Settings.Default.ImagesPath);
uriBuilder.Path += image;
_imagePath = uriBuilder.Uri;
</code></pre>

<p>I don't want to do any ugly string manipulation to make sure the base path ends with a trailing slash, etc.</p>
