Catch plugin exceptions at App.run() as well

include/sardine.py

@@ -119,4 +119,7 @@ class App:
         sys.exit(rv)
 
     def run(self):
-        print self.subcommand.get_output()
+        try:
+            print self.subcommand.get_output()
+        except SardinePluginError as e:
+            self.die(e, 10)