Don't check if importing a module emits a DeprecationWarning if the module is
implemented in C and the module is already loaded.

* Add py-bt-full command
* py-bt now gives an output similar to a regular Python traceback
* py-bt indicates:

  - if the garbage collector is running
  - if the thread is waiting for the GIL
  - detect PyCFunction_Call to get the name of the builtin function

Also fixes quoting to match 3.5+

Patch from Mattip.

Patch by Mark Roseman.

Patch from Pam McA'Nulty.

ElementTree Element objects.  Initial patch by Martin Panter.

to keep synchronized.

Patch from Chris Hogan of Intel, reviewed by Mark Dickinson.

Also fixes reporting of tests that change environment when there are no test
failures.

Patch from Terry Reedy

undefined behavior.

Patch by Jeffrey Armstrong.

Initial patch by Matt Frank.

editor font.  This should not affect current customized font selections.
Patch by Mark Roseman.