WIN32GUI - v1.4.3 released

- implemented Advanced Thread-safety for windows (so that any window can be accessed from any thread)
- created como-builder.exe - a tool for easier building the samples for Comeau compiler
- window_base::is_valid: added possibility to know whether a window is valid or not
(that is, has it already been destroyed, and you're still holding a reference?)
- added hyper_link, lite_html controls
- ported to gcc3.3.1
- increased the speed of wnd_shared_ptr - using InterlockedIncrement/Decrement from Peter Dimov
- added lots of debugging support
- window_base::destroy - works from any thread you call it.