#293 Exit code 0 when closing Debugger window

[siddhartha]

When exiting DOSBox by closing the Debugger window, an exit code of 0xc000013a is thrown. This can create problems for automated batch files when programming since it could be expecting code 0 for a successful execution. Also, on Windows 10, the Debugger window can be resized, messing up the formatting. On Windows 7 the window can still be resized, but it doesn't affect the window contents.

The patch exits with code 0 when the Debugger window is closed, disables the maximize button on the window, and also disables window resizing.