Update revisions.txt

Author: Federico Fissore

build/shared/revisions.txt

@@ -16,6 +16,7 @@ ARDUINO 1.6.6
 * Added Serial Plotter. Thanks @henningpohl
 * Editor: triple click selects whole line
 * Windows: IDE startup feels faster
+* Examples of libraries with a .development flag file in their root folder will not marked read-only. See #2619
 
 [libraries]