Don't grow strings by concatenation.  Use ''.join() instead.
include test data in the windows installer, so tests don't fail (closes #19866)
merge 2.7.7 release branch
Issue #21477: idle htests - lower case function names, other cleanups.
2.7.8 news section
Issue #21383: Allow "make touch" to work when building outside of the
source directory.
Issue #21383: OS X installer builds now use "make touch".
Issue 21198: Minor tarfile documentation bug.
Issue 21479: Fix markup for the TarFile.open() classmethod.
Issue #21545: Add .pop example and tweak comment about pure mutation methods.
Patch prepared by David Harrigan.
Issue #21523: Fix over-pessimistic computation of the stack effect of some opcodes in the compiler.

This also fixes a quadratic compilation time issue noticeable when compiling
code with a large number of "and" and "or" operators.
Issue #20635: Added tests for Tk geometry managers.
Issue #21522: Added Tkinter tests for Listbox.itemconfigure(),
PanedWindow.paneconfigure(), and Menu.entryconfigure().
Fixed new Tkinter tests added in issue #21522 with Tk 8.4.
Issue #18604: Skip the Tk instantiation test on OS X because it can
cause GUI tests to segfault in Cocoa Tk when run under regrtest -j
(multiple threads running subprocesses).
allow doc archives to be built for versions in the rc stage
Issue #21477: Idle htest: merge and modify run and runall; add many tests.
Patch by Saimadhav Heblikar
Issue #19925: Added tests for the spwd module. Original patch by Vajrasky Kok.
Issue 13355:  Make random.triangular degrade gracefully when low == high.
Issue 8743:  Improve interoperability between sets and the collections.Set abstract base class.