clamp setRetries() args & doc main page fixes (#709)

* clamp setRetries() args

* remove broken link to LttleWire on main pg

* update link to littlewire homepage

* renamed datasheets

* replace list of changes with a link to releases

Author: 2bndy5

RF24.cpp

@@ -1609,7 +1609,7 @@ void RF24::disableCRC(void)
 /****************************************************************************/
 void RF24::setRetries(uint8_t delay, uint8_t count)
 {
-    write_register(SETUP_RETR, (delay & 0xf) << ARD | (count & 0xf) << ARC);
+    write_register(SETUP_RETR, rf24_min(15, delay) << ARD | rf24_min(15, count));
 }
 
 /****************************************************************************/

RF24.h

@@ -2116,36 +2116,12 @@ class RF24 {
  *
  * @section News News
  *
- * **Aug 2020** <br>
- * v1.3.9
- * - Fix broken compilation for some devices due to recent changes
- * v1.3.8
- * - Introduces change that mainly reduces the time required to call RF24::startListening(), RF24::powerUp(), and RF24::powerDown()
- * - Affects speed of switching from TX->RX. Users might consider starting updates of slower devices with this<br>
- *   release to prevent missed packets when similar changes are introduced, affecting switching from RX->TX
- * - Clean up RF24::begin() function (reduce program size)
- *
- * v1.3.7
- * - Bug fix for RF24::writeFast() function affecting RF24 stack (all RF24 libraries)
- * - Unify Arduino & Linux constructor. Accept SPI speed in Hz as optional parameter
- * - Removal of BCM2835 SPI speed constants due to removal from BCM library
- * - Update to latest BCM2835 driver
- * - Bug fix for RPi millis() code
- * - Added Constant Carrier Wave functionality & added to scanner example
- * - Modify RF24::setPALevel() to allow setting LNA gain via optional parameter
- * - Cleanup of warnings, errors and old files
- *
- * **March-July 2020**
- * - Fixes for SPI_HAS_TRANSACTION detection (Affecting many devices)
- * - Add ability to configure SPI speed properly in Linux constructor
- * - Support multiple instances of SPIDEV on Linux
- * - Minor fixes & changes
- *
- *
+ * @li See the releases' descriptions on
+ * [the library's release page](http://github.com/nRF24/RF24/releases) for a list of
+ * changes.
  *
  * @section Useful Useful References
  *
- *
  * @li <a href="classRF24.html"><b>RF24 Class Documentation</b></a>
  * @li <a href="pages.html"><b>Support & Configuration</b></a>
  * @li <a href="https://github.com/nRF24/RF24/"><b>Source Code</b></a>
@@ -2176,7 +2152,7 @@ class RF24 {
  *
  * @li <a href="Arduino.html"><b>Arduino</b></a> (Uno, Nano, Mega, Due, Galileo, etc)
  * @li <a href="ATTiny.html"><b>ATTiny</b></a>
- * @li <a href="Linux.html"><b>Linux Installation</b></a>( <a href="RPi.html"><b>Linux/RPi General</b></a> , <a href="MRAA.html"><b>MRAA</b></a> supported boards ( Galileo, Edison, etc), <a href="LittleWire.html"><b>LittleWire</b></a>)
+ * @li <a href="Linux.html"><b>Linux Installation</b></a>( <a href="RPi.html"><b>Linux/RPi General</b></a> , <a href="MRAA.html"><b>MRAA</b></a> supported boards (Galileo, Edison, etc), LittleWire)
  * @li <a href="CrossCompile.html"><b>Cross-compilation</b></a> for linux devices
  * @li <a href="Python.html"><b>Python</b></a> wrapper available for Linux devices
  *
@@ -2199,7 +2175,7 @@ class RF24 {
  *
  * @li [0] https://learn.sparkfun.com/tutorials/tiny-avr-programmer-hookup-guide/attiny85-use-hints
  * @li [1] http://highlowtech.org/?p=1695
- * @li [2] http://littlewire.cc/
+ * @li [2] http://littlewire.github.io/
  * <br><br><br>
  *
  *