Install entrypoint scripts in develop command on Windows

[messense]

Closes #213

Per https://pythonhosted.org/distlib/tutorial.html#using-the-scripts-api:

On Windows, on systems where the PEP 397 launcher isn’t installed, it is not easy to ensure that the correct Python interpreter is used for a script. You may wish to install native Windows executable launchers which run the correct interpreter, based on a shebang line in the script.

This is not as portable as embedding the script into the binary launcher, but better than nothing.

[messense]

The test failure looks like rust-lang/rust#42869

[messense]

Even with PEP 397 launcher installed, .py and.pyw file extensions have to be properly associated with py.exe and pyw.exe to make scripts work. So I think this is somewhat useless, we have to go with the embedding the script into the binary launcher method to make it always work.

[davidhewitt]

Do you need me to test this on my machine? (IIRC you have a mac?)

[messense]

Do you need me to test this on my machine? (IIRC you have a mac?)

I've done some tests on a Windows VM, with file association correctly setup invoking the script in PowerShell works, but the test case somehow fails, I suspect it has something to do with Windows UNC path.

[messense]

@davidhewitt Please give it a try, looks like it's working on CI.

[messense]

Tested again in Windows VM and both entrypoint scripts and cargo test works. Merging.

[davidhewitt]

Sorry I didn't get around to testing this in time - I've had a busy recent few days!