Issue #13930: Adds ability for 2to3 to write its output to a different

directory tree instead of overwriting the input files.  Adds three command
line options: -o/--output-dir, -W/--write-unchanged-files and --add-suffix.

diff --cc Lib/lib2to3/refactor.py
Simple merge

diff --cc Misc/NEWS
index 4f15fd24046034a7a955d549fada83598ca1aab3,583673c3f60a6e7943a88fe63bc6229c83829a89..29d17fde29876f595a8bdacd5306f298e53def83
--- 1/Misc/NEWS
--- 2/Misc/NEWS
+++ b/Misc/NEWS
@@@ -466,6 -113,6 +466,10 @@@ Core and Builtin
  Library
  -------
  
++- Issue #13930: lib2to3 now supports writing converted output files to another
++  directory tree as well as copying unchanged files and altering the file
++  suffix.
++
  - Issue #9750: Fix sqlite3.Connection.iterdump on tables and fields
    with a name that is a keyword or contains quotes. Patch by Marko
    Kohtala.
@@@ -1927,18 -1369,8 +1931,23 @@@ IDL
  Tools/Demos
  -----------
  
++- Issue #13930: 2to3 is now able to write its converted output files to another
++  directory tree as well as copying unchanged files and altering the file
++  suffix.  See its new -o, -W and --add-suffix options.  This makes it more
++  useful in many automated code translation workflows.
++
 +- Issue #13628: python-gdb.py is now able to retrieve more frames in the Python
 +  traceback if Python is optimized.
 +
 +- Issue #11996: libpython (gdb), replace "py-bt" command by "py-bt-full" and
 +  add a smarter "py-bt" command printing a classic Python traceback.
 +
  - Issue #11179: Make ccbench work under Python 3.1 and 2.7 again.
  
 +- Issue #10639: reindent.py no longer converts newlines and will raise
 +  an error if attempting to convert a file with mixed newlines.
 +  "--newline" option added to specify new line character.
 +
  Extension Modules
  -----------------