Added window minimum sizes.

main.go

@@ -87,6 +87,11 @@ func wndProc(hwnd HWND, msg uint32, wParam WPARAM, lParam LPARAM) LRESULT {
 				MB_OK)
 		}
 		return 0
+	case WM_GETMINMAXINFO:
+		mm := lParam.MINMAXINFO()
+		mm.PtMinTrackSize.X = 320
+		mm.PtMinTrackSize.Y = 240
+		return 0
 	case WM_CLOSE:
 		err := DestroyWindow(hwnd)
 		if err != nil {

windows.go

@@ -306,3 +306,15 @@ const (
 	WM_WINDOWPOSCHANGED = 0x0047
 	WM_WINDOWPOSCHANGING = 0x0046
 )
+
+type MINMAXINFO struct {
+	PtReserved		POINT
+	PtMaxSize			POINT
+	PtMaxPosition		POINT
+	PtMinTrackSize		POINT
+	PtMaxTrackSize	POINT
+}
+
+func (l LPARAM) MINMAXINFO() *MINMAXINFO {
+	return (*MINMAXINFO)(unsafe.Pointer(l))
+}