Unit tests fail on Windows

[synapticarbors]

In preparing a conda recipe on conda-forge, I observed several tests failing on windows when appveyor tried to run the tests:

======================================================================
FAIL: test_get_app_key (tests.test_baseclient.BaseClientTest)
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Traceback (most recent call last):
  File "c:\users\josh\documents\github\betfairlightweight\tests\test_baseclient.py", line 94, in tes
t_get_app_key
    self.client.get_app_key()
AssertionError: AppKeyError not raised

======================================================================
FAIL: test_strip_datetime (tests.test_baseresource.BaseResourceInit)
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Traceback (most recent call last):
  File "c:\users\josh\documents\github\betfairlightweight\tests\test_baseresource.py", line 87, in t
est_strip_datetime
    assert type(stripped) == datetime.datetime
AssertionError

======================================================================
FAIL: test_strip_datetime_resource (tests.test_baseresource.BaseResourceInit)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "c:\users\josh\documents\github\betfairlightweight\tests\test_baseresource.py", line 116, in
test_strip_datetime_resource
    assert model_response.datetime_int == datetime.datetime.utcfromtimestamp(1465631675000 / 1e3)
AssertionError

----------------------------------------------------------------------
Ran 203 tests in 0.844s

FAILED (failures=3)

test_get_app_key:

This test fails because os.environ.get(self.username), where self.username=="username" returns a non-None response since USERNAME is a standard windows environment variable (note that Windows env variables are case insensitive).

test_strip_datetime:

Fails on py27 since integer is a long rather than an int. There is an easy fix for this.

test_strip_datetime_resource

There is a platform dependent exception that is raised so only catching ValueError is insufficient.

[liampauling]

Thanks Joshua, I took your two commits and changed the version before merging (makes life easier when updating pypi)