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/hd44780-lcd2usb.c

@@ -16,15 +16,12 @@
 # include "config.h"
 #endif
 
-#include <stdio.h>
 #include <stdlib.h>
-#include <string.h>
-#include <usb.h>
 
 #include "hd44780-lcd2usb.h"
+#include "hd44780-low.h"
 #include "report.h"
 
-
 /* connection type specific functions to be exposed using pointers in init() */
 void lcd2usb_HD44780_senddata(PrivateData *p, unsigned char displayID, unsigned char flags, unsigned char ch);
 void lcd2usb_HD44780_backlight(PrivateData *p, unsigned char state);