update revision log

Author: cmaglie

build/shared/revisions.txt

@@ -10,6 +10,9 @@ ARDUINO 1.6.10
 * Examples are now filtered by architecture
 
 [core]
+* avr: toolchain updated to latest Atmel release 3.5.2 http://distribute.atmel.no/tools/opensource/Atmel-AVR-GNU-Toolchain/3.5.2/
+  The updated tools are now binutils-2.26, gcc-4.9.2, avr-libc-2.0.0, gdb-7.8
+* avr: avrdude updated to version 6.3
 * fixed a small bug that caused a compile error on some 3rd party derivatives
   boards based on Leonardo
 * sam: added snprintf_P to avr/pgmspace.h stub. Thanks @jantje