Merge pull request #116 from Xenoamor/master

Add MOUSE_BACK and MOUSE_FORWARD to usb_mouse

keywords.txt

 MOUSE_MIDDLE	LITERAL1
 MOUSE_RIGHT	LITERAL1
 MOUSE_ALL	LITERAL1
+MOUSE_BACK	LITERAL1
+MOUSE_FORWARD	LITERAL1
 
 # USB Joystick
 Joystick	KEYWORD1

teensy3/usb_mouse.c

 
 // Set the mouse buttons.  To create a "click", 2 calls are needed,
 // one to push the button down and the second to release it
-int usb_mouse_buttons(uint8_t left, uint8_t middle, uint8_t right)
+int usb_mouse_buttons(uint8_t left, uint8_t middle, uint8_t right, uint8_t back, uint8_t forward)
 {
         uint8_t mask=0;
 
-        if (left) mask |= 1;
-        if (middle) mask |= 4;
-        if (right) mask |= 2;
+        if (left) mask    |= 1;
+        if (middle) mask  |= 4;
+        if (right) mask   |= 2;
+        if (back) mask    |= 8;
+        if (forward) mask |= 16;
         usb_mouse_buttons_state = mask;
         return usb_mouse_move(0, 0, 0);
 }

teensy3/usb_mouse.h

 #ifdef __cplusplus
 extern "C" {
 #endif
-int usb_mouse_buttons(uint8_t left, uint8_t middle, uint8_t right);
+int usb_mouse_buttons(uint8_t left, uint8_t middle, uint8_t right, uint8_t back, uint8_t forward);
 int usb_mouse_move(int8_t x, int8_t y, int8_t wheel);
 int usb_mouse_position(uint16_t x, uint16_t y);
 void usb_mouse_screen_size(uint16_t width, uint16_t height, uint8_t mac);
 #define MOUSE_LEFT 1
 #define MOUSE_MIDDLE 4
 #define MOUSE_RIGHT 2
-#define MOUSE_ALL (MOUSE_LEFT | MOUSE_RIGHT | MOUSE_MIDDLE)
+#define MOUSE_BACK 8
+#define MOUSE_FORWARD 16
+#define MOUSE_ALL (MOUSE_LEFT | MOUSE_RIGHT | MOUSE_MIDDLE | MOUSE_BACK | MOUSE_FORWARD)
 
 // C++ interface
 #ifdef __cplusplus
 		usb_mouse_move(0, 0, 0);
 	}
         void scroll(int8_t wheel) { usb_mouse_move(0, 0, wheel); }
-        void set_buttons(uint8_t left, uint8_t middle=0, uint8_t right=0) {
-		usb_mouse_buttons(left, middle, right);
+        void set_buttons(uint8_t left, uint8_t middle=0, uint8_t right=0, uint8_t back=0, uint8_t forward=0) {
+		usb_mouse_buttons(left, middle, right, back, forward);
 	}
         void press(uint8_t b = MOUSE_LEFT) {
 		uint8_t buttons = usb_mouse_buttons_state | (b & MOUSE_ALL);