[output/i3bar] Add flush method

flush() terminates a single iteration of widget drawing.

see #23

bumblebee/engine.py

@@ -52,6 +52,7 @@ class Engine(object):
             for module in self._modules:
                 widgets += module.widgets()
             self._output.draw(widgets)
+            self._output.flush()
 
         self._output.stop()
 

bumblebee/modules/test.py

@@ -8,4 +8,7 @@ class Module(bumblebee.engine.Module):
     def __init__(self, engine):
         super(Module, self).__init__(engine)
 
+    def widgets(self):
+        return []
+
 # vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4

bumblebee/output.py

@@ -29,4 +29,9 @@ class I3BarOutput(object):
             })
         sys.stdout.write(json.dumps(result))
 
+    def flush(self):
+        """Flushes output"""
+        sys.stdout.write(",\n")
+        sys.stdout.flush()
+
 # vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4