Header fixes:

* Do not include system headers in shared files (stdlib.h).
* Don't include lcd.h only once in each driver.
* Remove some unnecessary headers from driver (e.g. syslog.h)
* Include <poll.h> instead of <sys/poll.h>
* Spelling fixes.

server/drivers/lcd_lib.c

@@ -8,10 +8,6 @@
  *       the height of hbars, etc.
  */
 
-#include <stdlib.h>
-#include <unistd.h>
-#include <string.h>
-
 #include "lcd.h"
 
 #ifdef HAVE_CONFIG_H