Allow mpv-1.dll to be placed in python script directory (#96)

Windows: Look for DLL in script directory

Loading DLLs through ctypes on Windows is a mess. ctypes looks in PATH, which is different from the Windows built-in DLL loading system. By default ctypes looks next to python.exe, but you might not want to install python script dependencies next to the system-wide python interpreter.

This commit adds a fallback looking for mpv-1.dll in the same directory the mpv.py script is placed in to allow people to use python-mpv with a minimum in configuration. You can still control loading behavior through PATH. For details on this, consult the following stackoverflow answer: https://stackoverflow.com/a/23805306

mpv.py

@@ -28,7 +28,10 @@ import re
 import traceback
 
 if os.name == 'nt':
-    backend = CDLL('mpv-1.dll')
+	try:
+		backend = CDLL('mpv-1.dll')
+	except FileNotFoundError:
+		backend = CDLL(os.path.join(os.path.dirname(os.path.abspath(__file__)), 'mpv-1.dll'))
     fs_enc = 'utf-8'
 else:
     import locale