Win32 console uses pinvoke for buffer updates

[serialseb]

Currently the console code uses cursor positoning and some crazy movebuffer code to provide notification. This makes the screen flicker, which is not good, but was quick and easy to get to and is without pinvoke.

Code should be preserved for the case where mono starts supporting movebuffer on tty (possible patch?), but a new one should be built using win32 pinvoke to read/write to the buffer and track console window movements.