Update revisions.txt

Author: Federico Fissore

build/shared/revisions.txt

@@ -6,6 +6,8 @@ ARDUINO 1.6.5
 * New editor, based on RSyntaxTextArea. Thanks @ricardojlrufino
 * New keywords. Thanks @Chris--A
 * Easier "additional boards manager url" field: a wide text area opens by clicking the added button (right side of the text field)
+* Rewritten code of Preferences window: its content is now correctly drawn on every OS
+* Fixed a bug that made the IDE notify users of invalid libraries too many times. Thanks @Chris--A
 
 [libraries]
 * LiquidCrystal fixes. Thanks @newbie15