title: Maketrans not working for petl with python3.4
body: <p>I am using petl package which i have installed using pip  in virtulaenv with python 3.4. when i tried to test that whether the petl package is installed properly or not in the python shell 
  I have done this to check </p>
  
  <pre><code>$ python 
  Python 3.4.0 (default, Apr 11 2014, 13:05:11) 
  [GCC 4.8.2] on linux
  Type "help", "copyright", "credits" or "license" for more information.
  &gt;&gt;&gt; from petl import *
  Traceback (most recent call last):
    File "&lt;stdin&gt;", line 1, in &lt;module&gt;
    File "/home/user/.env/lib/python3.4/site-packages/petl/__init__.py", line 10, in &lt;module&gt;
      from petl.util import header, fieldnames, data, records, rowcount, look, see, \
    File "/home/user/.env/lib/python3.4/site-packages/petl/util.py", line 14, in &lt;module&gt;
      from string import maketrans
  ImportError: cannot import name 'maketrans'
  &gt;&gt;&gt;
  </code></pre>
  
  <p>I tried to check whether  maketrans is present in  string package i run this </p>
  
  <pre><code>&gt;&gt;&gt; from string import maketrans
  Traceback (most recent call last):
    File "&lt;stdin&gt;", line 1, in &lt;module&gt;
  ImportError: cannot import name 'maketrans'
  &gt;&gt;&gt; 
  </code></pre>
  
  <p>Found that the default python string package does not have this . I am not sure that why petl package have used this without mentioning it in its dependency and if its the default python package then why its giving import error. </p>
  
  <p>Not sure what is happening can any one please help </p>