Move items from NEWS to idlelib/NEWS.txt. Standardize headers spacing: 2 lines

above "What's New and 0 lines above "Release date".  Remove most old headers
for non-final releases (they currently do not get carried forward.

diff --cc Lib/idlelib/NEWS.txt
index be063c4cc06586d08bf601c36a2ce4e5bd1a6e41,daf54bc8cbac5706943f83189717a7099d8033a5..22a5184e3a899518a1ca7ea00a7ca877cb402cfd
--- 1/Lib/idlelib/NEWS.txt
--- 2/Lib/idlelib/NEWS.txt
+++ b/Lib/idlelib/NEWS.txt
@@@ -1,6 -1,26 +1,26 @@@
 -What's New in IDLE 3.5.1?
 -=========================
 -*Release date: 2015-09-13*
++What's New in IDLE 3.6.0a1?
++===========================
++*Release date: 2017?*
+ 
+ - Issue #25199: Idle: add synchronization comments for future maintainers.
+ 
+ - Issue #16893: Replace help.txt with idle.html for Idle doc display.
+   The new idlelib/idle.html is copied from Doc/build/html/idle.html.
+   It looks better than help.txt and will better document Idle as released.
+   The tkinter html viewer that works for this file was written by Rose Roseman.
+   The now unused EditorWindow.HelpDialog class and helt.txt file are deprecated.
+ 
+ - Issue #24199: Deprecate unused idlelib.idlever with possible removal in 3.6.
+ 
+ - Issue #24782: In Idle extension config dialog, replace tabs with sorted list.
+   Patch by Mark Roseman.
+ 
+ - Issue #24790: Remove extraneous code (which also create 2 & 3 conflicts).
+ 
+ 
  What's New in IDLE 3.5.0?
  =========================
- *Release date: 2015-09-13* ??
+ *Release date: 2015-09-13*
  
  - Issue #23672: Allow Idle to edit and run files with astral chars in name.
    Patch by Mohd Sanad Zaki Rizvi.
@@@ -223,11 -239,6 +244,11 @@@ What's New in IDLE 2.7? (UNRELEASED, bu
  
  - Issue #3549: On MacOS the preferences menu was not present
  
- What's New in IDLE 3.0 final?
- =============================
 +
++What's New in IDLE 3.0?
++=======================
 +*Release date: 03-Dec-2008*
 +
  - IDLE would print a "Unhandled server exception!" message when internal
    debugging is enabled.