first pass at alert buttons

They work fine. But I had to go to a lot of trouble to get Yesod to render
routes in a pure function. It may instead make more sense to have each
alert have an assocated IO action, and a single route that runs the IO
action of a given alert id. I just wish I'd realized that before the past
several hours of struggling with something Yesod really doesn't want to
allow.

Assistant/Threads/WebApp.hs

@@ -49,10 +49,11 @@ webAppThread
 	-> ScanRemoteMap
 	-> TransferQueue
 	-> TransferSlots
+	-> UrlRenderer
 	-> Maybe (IO String)
 	-> Maybe (Url -> FilePath -> IO ())
 	-> NamedThread
-webAppThread mst dstatus scanremotes transferqueue transferslots postfirstrun onstartup = thread $ do
+webAppThread mst dstatus scanremotes transferqueue transferslots urlrenderer postfirstrun onstartup = thread $ do
 	webapp <- WebApp
 		<$> pure mst
 		<*> pure dstatus
@@ -64,14 +65,16 @@ webAppThread mst dstatus scanremotes transferqueue transferslots postfirstrun on
 		<*> pure $(embed "static")
 		<*> newWebAppState
 		<*> pure postfirstrun
+	setUrlRenderer urlrenderer $ yesodRender webapp (pack "")
 	app <- toWaiAppPlain webapp
 	app' <- ifM debugEnabled
 		( return $ httpDebugLogger app
 		, return app
 		)
-	runWebApp app' $ \port -> case mst of
-		Nothing -> withTempFile "webapp.html" $ \tmpfile _ -> go port webapp tmpfile
-		Just st -> go port webapp =<< runThreadState st (fromRepo gitAnnexHtmlShim)
+	runWebApp app' $ \port -> do
+		case mst of
+			Nothing -> withTempFile "webapp.html" $ \tmpfile _ -> go port webapp tmpfile
+			Just st -> go port webapp =<< runThreadState st (fromRepo gitAnnexHtmlShim)
 	where
 		thread = NamedThread thisThread
 		getreldir Nothing = return Nothing