Allow customization of error page

Author: technicalguru

src/WebApp/Application.php

@@ -329,6 +329,10 @@ public function getMenu($id = NULL) {
 		return NULL;
 	}
 
+	public function getErrorPage($httpCode) {
+		return NULL;
+	}
+
 	/**
 	 * Persist any error message in the database.
 	 */

src/WebApp/Theme.php

@@ -184,8 +184,9 @@ public function hasFeature($name) {
 	}
 
 	public function getErrorPage($htmlCode) {
-		$name = '\\WebApp\\Error\\ErrorPage';
-		return new $name($this->app, $htmlCode, 'Error');
+		$rc = $this->app->getErrorPage($htmlCode);
+		if ($rc == NULL) $rc = new \WebApp\Error\ErrorPage($this->app, $htmlCode, 'Error');
+		return $rc;
 	}
 }