Fixed major bug: drivers that accepted size arguments could wind

up with more than 80 characters (20x4) in their display, and thus
overwrite memory outside of the allocated 80 characterwframebuffer.

For example, using a 20x6 screen would do this.

All drivers now either ignore a missing framebuffer, or allocate it
themselves - the latter is prefered.

server/drivers/lb216.c

@@ -196,15 +196,6 @@ int LB216_init(lcd_logical_driver *driver, char *args)
    LB216_hidecursor();
    LB216_backlight(backlight_brightness);
 
-   
-   if(!driver->framebuf)
-   {
-      fprintf(stderr, "LB216_init: No frame buffer.\n");
-      driver->close();
-      return -1;
-   }
-
-
    // Set the functions the driver supports...
 
    driver->clear =      LB216_clear;