Adding soft entry bootloader via key sequence.

- Fixed up basic Macro module (still not to my liking)
- Added the bootloader entry bits
- Added logic for key sequence tracking

USB/pjrc/usb_com.c

@@ -79,7 +79,8 @@ inline void usb_send(void)
 		// Send keypresses
 		usb_keyboard_send();
 
-		// Clear modifiers
+		// Clear modifiers and keys
 		USBKeys_Modifiers = 0;
+		USBKeys_Sent      = 0;
 }