Try UNIXy and Windowsy ways of setting locale

[mdboom]

And warn, rather than fail, if both methods fail.

In response to comments in #2368

[dmcdougall]

I like the warning. Thanks @mdboom.

[cgohlke]

Works for me. Thank you.

[pelson]

These bare excepts are pretty unfriendly - not my favourite solution. Do you know which exceptions we should be trapping?

[pelson]

$> python tests.py matplotlib.tests.test_legend       
E
======================================================================
ERROR: test suite for <module 'matplotlib.tests.test_legend' from 'build/lib.linux-x86_64-2.7/matplotlib/tests/test_legend.py'>
----------------------------------------------------------------------
Traceback (most recent call last):
  File "lib/python2.7/site-packages/nose-1.1.2-py2.7.egg/nose/suite.py", line 208, in run
    self.setUp()
  File "lib/python2.7/site-packages/nose-1.1.2-py2.7.egg/nose/suite.py", line 291, in setUp
    self.setupContext(ancestor)
  File "lib/python2.7/site-packages/nose-1.1.2-py2.7.egg/nose/suite.py", line 314, in setupContext
    try_run(context, names)
  File "lib/python2.7/site-packages/nose-1.1.2-py2.7.egg/nose/util.py", line 478, in try_run
    return func()
  File "build/lib.linux-x86_64-2.7/matplotlib/tests/__init__.py", line 17, in setup
    locale.setlocale(locale.LC_ALL, 'en_US.UTF-8')
  File "lib/python2.7/locale.py", line 530, in setlocale
    locale = normalize(_build_localename(locale))
  File "lib/python2.7/locale.py", line 438, in _build_localename
    language, encoding = localetuple
ValueError: too many values to unpack

----------------------------------------------------------------------
Ran 0 tests in 0.013s

FAILED (errors=1)

I'd have said that this was because matplotlib.tests has a from __future__ import unicode_literals and there is a test in the python (v2.7.2) which goes: if locale and type(locale) is not type(""):

The Python bug http://bugs.python.org/issue3067 has been resolved in v2.7.3 by the looks of it. In short, I'm amazed this works on Python 2.6 at all. And it certainly doesn't work for Python v2.7.<3.

[pelson]

My bad, I see this is resolved in #2386.