Enable build and sign on Windows

[zooba]

This script can be run to generate a semi-pure wheel that includes precompiled extension modules for 3.5 and 3.6, both 32-bit and 64-bit. (Python 3.5 is when Windows started using ABI suffix on extension modules - we can't replicate this as easily for earlier versions.) I already have an internal build definition using this that can also sign all the binaries as needed.

I also fixed #112 by changing how we build the extension modules (i.e. with the correct names). I'm also not quite sure why the default_return_value change became necessary, but it was, so I assume it was one of our patches?

[int19h]

@karthiknadig, can you take a look at default_return_value stuff?

[karthiknadig]

@zooba default_return_value change was done to fix the conditional breakpoints in pydevd. It was this change that did that 63e93ec

[zooba]

Okay, I removed the parameter. Can you confirm that it should be returning False/None in this case?

[karthiknadig]

It should return False, that makes the intent of returning there clearer.

[zooba]

Done. The else block of that function needs looking at too, as it doesn't return anything (and arguably if the condition is broken it should return True so that we break, right?).

But file it separately - we need this PR merged before we can build for today's bug bash.