Delete empty mojo python package, and prefix all python packages with mojo_

mojo/python/tests/runloop_unittest.py

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import mojo_unittest
 
 # pylint: disable=E0611
-from mojo import system
+import mojo_system as system
 
 
 def _Increment(array):
   def _Closure():
     array.append(0)
   return _Closure
 
 
 class RunLoopTest(mojo_unittest.MojoTestCase):
 
@@ skipping 13 matching lines @@
     with self.assertRaisesRegexp(Exception, '^error$'):
       self.loop.Run()
     self.assertEquals(len(array), 0)
     self.loop.RunUntilIdle()
     self.assertEquals(len(array), 1)
 
   def testCurrent(self):
     self.assertEquals(system.RunLoop.Current(), self.loop)
     self.loop = None
     self.assertIsNone(system.RunLoop.Current())