Call ssl.create_default_context conditionally, depending on the pytho…

[afester]

#59 added a call to ssl.create_default_context which is only available starting with Python 2.7.9. At least FreeCad 0.16 build 6712 on Windows 10 still uses Python 2.7.8.
This pull request encapsulates the call to urllib2.connect() and only calls ssl.create_default_context when the Python version is 2.7.9 or later.

[OctagonHex]

I think there is an error, the openUrl helper function:
it reads in the second branch:
return urllib2.urlopen(url)
instead of
return urllib2.urlopen(url, , context=ctx)
otherwise the context is never used.

[elanlb]

Yes, I agree with @OctagonHex , you defined a variable for the context but you didn't actually use it. I added this context thing to every class regardless of the Python version in this commit, so you can look at that and see an example of the implementation. The urlopen function should be called like this: urllib2.urlopen("https://github.com/FreeCAD/FreeCAD-addons", context=ctx)

(This is also an improvement to issue #11 )

[afester]

Absolutely correct, my bad - I was probably too much in a hurry to get the code updated for the #57 PR ... Will fix that and update the PR