rework HID-based libraries and add Due fallback

Author: facchinm

README.adoc

@@ -0,0 +1,25 @@
+= Keyboard Library for Arduino =
+
+This library allows an Arduino board with USB capabilites to act as a Keyboard.
+Being based on HID library you need to include "HID.h" in your sketch.
+
+For more information about this library please visit us at
+http://www.arduino.cc/en/Reference/Keyboard
+
+== License ==
+
+Copyright (c) Arduino LLC. All right reserved.
+
+This library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Lesser General Public
+License as published by the Free Software Foundation; either
+version 2.1 of the License, or (at your option) any later version.
+
+This library is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public
+License along with this library; if not, write to the Free Software
+Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA

keywords.txt

@@ -0,0 +1,24 @@
+#######################################
+# Syntax Coloring Map For Keyboard
+#######################################
+
+#######################################
+# Datatypes (KEYWORD1)
+#######################################
+
+Keyboard	KEYWORD1
+
+#######################################
+# Methods and Functions (KEYWORD2)
+#######################################
+
+begin	KEYWORD2
+write	KEYWORD2
+press	KEYWORD2
+release	KEYWORD2
+releaseAll	KEYWORD2
+
+#######################################
+# Constants (LITERAL1)
+#######################################
+

library.properties

@@ -0,0 +1,9 @@
+name=Keyboard
+version=1.0.0
+author=Arduino
+maintainer=Arduino <[email protected]>
+sentence=Allows an Arduino board with USB capabilites to act as a Keyboard. For Leonardo/Micro only
+paragraph=This library plugs on the HID library. It can be used with or without other HID-based libraries (Mouse, Gamepad etc)
+category=USB
+url=http://www.arduino.cc/en/Reference/Keyboard
+architectures=*

Keyboard.cpp renamed to src/Keyboard.cpp

@@ -19,10 +19,10 @@
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
 
-#if 1
-
 #include "Keyboard.h"
 
+#if defined(_USING_HID)
+
 //================================================================================
 //================================================================================
 //	Keyboard

Keyboard.h renamed to src/Keyboard.h

@@ -22,15 +22,13 @@
 #ifndef KEYBOARD_h
 #define KEYBOARD_h
 
-#if 0 //defined(_USING_HID)
-
-#error "Can only attach one submodule to HID module"
+#include "HID.h"
 
-#else
+#if !defined(_USING_HID)
 
-#define _USING_HID
+#warning "Using legacy HID core (non pluggable)"
 
-#include "HID.h"
+#else
 
 //================================================================================
 //================================================================================