Fix CRC16 path (#424)

lib/CRC16/LICENSE

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+The MIT License (MIT)
+
+Copyright (c) 2014 Vincenzo Mennella
+
+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:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+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.

lib/CRC16/examples/Crc16_Example/Crc16_Example.ino

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+#include <Crc16.h>
+//Crc 16 library (XModem)
+Crc16 crc; 
+
+void setup()
+{
+    Serial.begin(38400); 
+    Serial.println("CRC-16 bit test program");
+    Serial.println("=======================");
+  
+}
+
+void loop()
+{
+  /*
+    Examples of crc-16 configurations
+    Kermit: width=16 poly=0x1021 init=0x0000 refin=true  refout=true  xorout=0x0000 check=0x2189
+    Modbus: width=16 poly=0x8005 init=0xffff refin=true  refout=true  xorout=0x0000 check=0x4b37
+    XModem: width=16 poly=0x1021 init=0x0000 refin=false refout=false xorout=0x0000 check=0x31c3
+    CCITT-False:width=16 poly=0x1021 init=0xffff refin=false refout=false xorout=0x0000 check=0x29b1
+    see http://www.lammertbies.nl/comm/info/crc-calculation.html
+  */
+  //calculate crc incrementally
+  byte data[] = "123456789";
+  
+  Serial.println("Calculating crc incrementally");
+  
+  crc.clearCrc();
+  for(byte i=0;i<9;i++)
+  {
+     Serial.print("byte ");
+     Serial.print(i);
+     Serial.print(" = ");
+     Serial.println(data[i]);
+     crc.updateCrc(data[i]);
+  }
+  unsigned short value = crc.getCrc();
+  Serial.print("crc = 0x");
+  Serial.println(value, HEX);
+  
+  Serial.println("Calculating crc in a single call");
+  
+  //XModem
+  value = crc.XModemCrc(data,0,9);
+  Serial.print("XModem crc = 0x");    
+  Serial.println(value, HEX);
+  //Reference xmodem
+  Serial.println("Reference XModem crc");
+  value = calcrc((char*)data, 9);
+  Serial.print("crc = 0x");    
+  Serial.println(value, HEX);
+
+  //Modbus
+  value = crc.Modbus(data,0,9);
+  Serial.print("Modbus crc = 0x");    
+  Serial.println(value, HEX);
+
+  //Mcrf4XX
+  value = crc.Mcrf4XX(data,0,9);
+  Serial.print("Mcrf4XX crc = 0x");    
+  Serial.println(value, HEX);
+
+  while(true);
+}
+//Check routine taken from
+//http://web.mit.edu/6.115/www/miscfiles/amulet/amulet-help/xmodem.htm
+int calcrc(char *ptr, int count)
+{
+    int  crc;
+    char i;
+    crc = 0;
+    while (--count >= 0)
+    {
+        crc = crc ^ (int) *ptr++ << 8;
+        i = 8;
+        do
+        {
+            if (crc & 0x8000)
+                crc = crc << 1 ^ 0x1021;
+            else
+                crc = crc << 1;
+        } while(--i);
+    }
+    return (crc);
+}

lib/CRC16/keywords.txt

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+#######################################
+# Syntax Coloring Map For CRC16
+#######################################
+
+#######################################
+# Datatypes (KEYWORD1)
+#######################################
+Crc16	KEYWORD1
+#######################################
+# Methods and Functions (KEYWORD2)
+#######################################
+clearCrc	KEYWORD2
+updateCrc	KEYWORD2
+getCrc	KEYWORD2
+fastCrc	KEYWORD2
+XModemCrc	KEYWORD2
+Mcrf4XX	KEYWORD2
+Modbus	KEYWORD2
+
+#######################################
+# Constants (LITERAL1)
+#######################################

lib/CRC16/readme.md

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+# Crc16 A simple crc-16 library for Arduino
+
+## Description
+Use this library to implement crc checks on buffer arrays
+
+## Usage
+There are two modes to calculate crc: incremental and single call:
+* In first mode the crc is calculated adding data bytes one by one and then calculating final crc, this is useful
+for reception routines that receives bytes asynchrously,
+* The second mode is used to obtain crc from a buffer array.
+Using one mode doesn't interfere with the other (So you can calculate tx crc while receiving data and updating rx crc)
+
+Is possible to configure crc with all crc-16bit standards (by default is defined XModem).
+
+See possible crc variants:
+http://www.lammertbies.nl/comm/info/crc-calculation.html 
+
+
+