Start of rendering partials.

src/renderer/renderer.rs

@@ -172,6 +172,10 @@ impl<'a> DustRenderer<'a> {
                     };
                 }
             }
+            DustTag::DTPartial(partial) => {
+                let rendered_content = self.render(&partial.name, breadcrumbs)?;
+                return Ok(rendered_content);
+            }
             _ => (), // TODO: Implement the rest
         }
         Ok("".to_owned())