Several functions adopted the strategy of altering a full lengthed
string copy and resizing afterwards.  That would fail if the initial
string was short enough (0 or 1) to be interned.  Interning precluded
the subsequent resizing operation.

The solution was to make sure the initial string was at least two
characters long.

Added tests to verify that all binascii functions do not crater when
given an empty string argument.

Fix open Verbs.
Properly add "Edit with IDLE" to TclTk feature.

* Discuss the algorithmic distinctions between s.split() and s.split(sep).
* Document the split behavior for empty strings.
* Note the behavior when maxsplit is zero.
* Include short examples.

you leap" approach.  Makes the early call to os.urandom() unnecessary.

* Complete the previous patch by making sure that the MachineRandom
  tests are only run when the underlying resource is available.

"all or none" to "all or some".

This provides much greater test coverage without eating much time.
It also makes it more likely that routine regression testing will
unearth bugs.

in the new docs.

DocTestRunner.__run:  Separate the determination of the example outcome
from reporting that outcome, to squash brittle code duplication and
excessive nesting.

ignoring their transaction (txn) argument.

* trap NotImplementedError raised by os.urandom calls when not available
  on a particular system.

empty final matches with finditer(). New test cases included
for this bug and for #581080.

some escaping bugs in SRE.

this is the right way to document such things (Fred, help me out here :-),
but I got misled by the existing documentation and assumed the parameter
list was a *args sort of thing.

[Bug #1011606] Only check file descriptors for exceptional conditions if the fd is readable or writable

(Contributed by Dima Dorfman)

- wrap long line