Add items to MISC/NEWS and idlelib/NEWS.txt.

Lib/idlelib/NEWS.txt

+What's New in IDLE 2.7.12?
+==========================
+*Release date: 2015-06-30?*
+
+- Issue #26673: When tk reports font size as 0, change to size 10.
+  Such fonts on Linux prevented the configuration dialog from opening.
+
+- Issue #27044: Add ConfigDialog.remove_var_callbacks to stop memory leaks.
+
+- In the 'IDLE-console differences' section of the IDLE doc, clarify
+  how running with IDLE affects sys.modules and the standard streams.
+
+- Issue #25507: fix incorrect change in IOBinding that prevented printing.
+  Change also prevented saving shell window with non-ascii characters.
+  Augment IOBinding htest to include all major IOBinding functions.
+
+- Issue #25905: Revert unwanted conversion of ' to ’ RIGHT SINGLE QUOTATION
+  MARK in README.txt and open this and NEWS.txt with 'ascii'.
+  Re-encode CREDITS.txt to utf-8 and open it with 'utf-8'.
+
+- Issue #26417: Prevent spurious errors and incorrect defaults when
+  installing IDLE 2.7 on OS X: default configuration settings are
+  no longer installed from OS X specific copies.
+
+
 What's New in IDLE 2.7.11?
 ==========================
 *Release date: 2015-12-06*

Misc/NEWS

@@ -253,6 +253,22 @@ Library
 IDLE
 ----
 
+- Issue #26673: When tk reports font size as 0, change to size 10.
+  Such fonts on Linux prevented the configuration dialog from opening.
+
+- Issue #27044: Add ConfigDialog.remove_var_callbacks to stop memory leaks.
+
+- In the 'IDLE-console differences' section of the IDLE doc, clarify
+  how running with IDLE affects sys.modules and the standard streams.
+
+- Issue #25507: fix incorrect change in IOBinding that prevented printing.
+  Change also prevented saving shell window with non-ascii characters.
+  Augment IOBinding htest to include all major IOBinding functions.
+
+- Issue #25905: Revert unwanted conversion of ' to ’ RIGHT SINGLE QUOTATION
+  MARK in README.txt and open this and NEWS.txt with 'ascii'.
+  Re-encode CREDITS.txt to utf-8 and open it with 'utf-8'.
+
 - Issue #26417: Prevent spurious errors and incorrect defaults when
   installing IDLE 2.7 on OS X: default configuration settings are
   no longer installed from OS X specific copies.