[telemetry] Sort imports in Telemetry and its dependents.

tools/perf/page_sets/pica.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.
+
 from telemetry.page import page_set as page_set_module
+
 from measurements import polymer_load
 
 
 class PicaPage(polymer_load.PageForPolymerLoad):
 
   def __init__(self, page_set):
     super(PicaPage, self).__init__(
       url='http://localhost/polymer/projects/pica/',
       page_set=page_set)
     self.archive_data_file = 'data/pica.json'
 
 
 class PicaPageSet(page_set_module.PageSet):
 
   """ Pica demo app for the Polymer UI toolkit """
 
   def __init__(self):
     super(PicaPageSet, self).__init__(
       archive_data_file='data/pica.json',
       bucket=page_set_module.INTERNAL_BUCKET)
 
     self.AddUserStory(PicaPage(self))