Provide portable PySide2 wheel via pip

Here's a formal request to make it easier to distribute PySide2 using a wheel.

• Portable (do not require Qt installed, bundle it in the wheel)
• Pip-installable (without compiling during install), distributed via PyPi.
• Compatible with Python 2.7 and 3.5/3.6
• Bundle the pyside2-uic binary and make it work without errors: https://bugreports.qt.io/browse/PYSIDE-357
• Review and rewrite setup.py. It's not up to today's standards in terms of packaging.
• Definitively include PySide2.QtUiTools (requires Qt Creator on build) and requires fixing https://bugreports.qt.io/browse/PYSIDE-552
• Built against Qt 5.6
• Add some form of way of figuring out which version of PySide2 is used: https://bugreports.qt.io/browse/PYSIDE-557 (or better, maintain the _version_ string)
• Windows, macOS and "Manylinux" support

You may argue that PySide2 is not yet at a stable release, but users are starting to rely on it – and although I don't want to get political – I see PySide2 already loosing out on adoption because of this hurdle. I far too often see people move to PyQt5 just because you can just pip-install that and move on with work/life and achieve results.