py3compat.py fails flake8 testing on Python 3
py3compat.py fails flake8 testing on Python 3

py3compat.py is "vendored" into _many_ other project so all of those projects also fail flake8 testing on Python 3.  :-(

To turn on automated testing, you would need to do steps 1 and 2 at https://docs.travis-ci.com/user/getting-started

flake8 testing of https://github.com/yeleman/py3compat on Python 3

`# stop the build if there are Python syntax errors or undefined names`
$ __flake8 . --count --select=E901,E999,F821,F822,F823 --show-source --statistics__ 
```
./py3compat.py:57:17: F821 undefined name 'unicode'
    text_type = unicode
                ^

./py3compat.py:58:18: F821 undefined name 'xrange'
    range_type = xrange
                 ^

./py3compat.py:59:26: F821 undefined name 'unicode'
    string_types = (str, unicode)
                         ^

./py3compat.py:87:33: F821 undefined name 'unicode'
        if isinstance(filename, unicode):
                                ^
```
yeleman/py3compat