Adding in USB module updates from Teensyduino 1.18rc2.

- For potential bug fixes
- Not copied verbatim, some additions were left out

Output/pjrcUSB/arm/usb_keyboard.c

@@ -1,3 +1,33 @@
+/* Teensyduino Core Library
+ * http://www.pjrc.com/teensy/
+ * Copyright (c) 2013 PJRC.COM, LLC.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * 1. The above copyright notice and this permission notice shall be 
+ * included in all copies or substantial portions of the Software.
+ *
+ * 2. If the Software is incorporated into a build system that allows 
+ * selection among a list of target devices, then similar target
+ * devices manufactured by PJRC.COM must be included in the list of
+ * target devices and selectable in the same manner.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
 #include "usb_dev.h"
 #include "usb_keyboard.h"
 #include <Lib/USBLib.h>
@@ -22,7 +52,7 @@ static uint8_t transmit_previous_timeout=0;
 
 
 // send the contents of keyboard_keys and keyboard_modifier_keys
-uint8_t usb_keyboard_send(void)
+int usb_keyboard_send(void)
 {
 	uint32_t wait_count=0;
 	usb_packet_t *tx_packet;