WIN32GUI v1.6.4 released

- Advanced subclassing: you can now subclass any window
from your program, easy and flexible! You can, for example,
handle events from all your windows, in about 5-10 lines of code!
Check out the examples/advanced_subclassing.
- Win32GUI Spy: Know your application inside out! Yet another
way to spy on your programs. Advanced filtering included.