Unicode encoding in import errors - Fix for issue #346

[friedererdmann]

If Python 2, and import error message is unicode, encode as ascii before casting to string to avoid UnicodeDecodeError.

Fix for #346

Typical example of error message that triggers a UnicodeDecodeError:

DLL load failed : le module spécifié est introuvable.

Typical use case where this happens:

French Windows language and trying to use Qt.py in application with Python 2 and unicode strings.

Isolated behavior:

import sys
text = str(u"DLL load failed : le module spécifié est introuvable.".encode('ascii', 'replace'))
>> b'DLL load failed : le module sp?cifi? est introuvable.'

[CLAassistant]

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[mottosso]

This looks good, thanks for this. Now, can you think of any way to actually test this? :S Ideally, we'd run it on a non-English OS, but in the context of Travis I'm not sure how to do that..

Also, I just noticed Travis isn't even being called! Investingating..

[mottosso]

There we go, looks like there's another complaint regarding the unicode variable.

[mottosso]

Looks good, let's give it a try!