MSS.__init__ throws AttributeError due to SetProcessDPIAware on XP

[foone]

General information:

• OS name: Windows
• OS version: XP 5.1.2600
• OS architecture: 32 bits
• Resolutions:
  • Monitor 1: 1920x975
• Python version: 2.7.13
• MSS version: 4.0.1

Description of the warning/error

MSS.__init__ fails to initialize on XP because when SetProcessDpiAwareness fails, it falls back to SetProcessDPIAware, which was added in Vista. Wrapping it in another try/except for the Attribute error makes it work fine. (I tried to make a pull request but ran into issues with github's UI and gave up, but it's a minor fix)

Full message

Traceback (most recent call last):
  File "sc2k.py", line 58, in <module>
    take_screenshot(filename)
  File "sc2k.py", line 30, in take_screenshot
    with mss.mss() as sct:
  File "C:\Python27\lib\site-packages\mss\factory.py", line 38, in mss
    return MSS(**kwargs)
  File "C:\Python27\lib\site-packages\mss\windows.py", line 92, in __init__
    self.user32.SetProcessDPIAware()
  File "C:\Python27\lib\ctypes\__init__.py", line 379, in __getattr__
    func = self.__getitem__(name)
  File "C:\Python27\lib\ctypes\__init__.py", line 384, in __getitem__
    func = self._FuncPtr((name_or_ordinal, self))
AttributeError: function 'SetProcessDPIAware' not found

[BoboTiG]

Hello,

XP! :) Would you mind open a PR? It would be great.

[BoboTiG]

I just published 4.0.2 with your patch ;)