Issue #19619: Blacklist non-text codecs in method API

str.encode, bytes.decode and bytearray.decode now use an
internal API to throw LookupError for known non-text encodings,
rather than attempting the encoding or decoding operation and
then throwing a TypeError for an unexpected output type.

The latter mechanism remains in place for third party non-text
encodings.
Issue #19619: Update What's New for codec blacklist
Update bundled pip to 1.5rc1
Close #19552: venv and pyvenv ensurepip integration
Close #17916: dis.Bytecode based replacement for distb

- Bytecode.from_traceback() alternate constructor
- current_offset parameter and attribute

Patch by Claudiu Popa
Issue #17134: check certs of CA and ROOT system store
Issue #19448: report name / NID in exception message of ASN1Object
A fix for issue 19555 on Windows.
Trunk merge.
Implement PEP 451 (ModuleSpec).
Issue #19673: Add pathlib to the stdlib as a provisional module (PEP 428).
Fix whitespace
Fix test failure under systems with an incompatible locale
Don't assume trying to find a builtin will succeed (e.g. posix isn't on Windows)
Hopefully fix test_is_socket_true
Remove a commented-out line
Update SQLite to 3.8.1 on Windows.
Update xz to 5.0.5.
Make some tests more verbose in the face of failure
Issue #18864: Don't try and use unittest as a testing module for
built-in loading; leads to a reload scenario where attributes get set
which are wrong after the test.