Dimitrios Apostolou authored 4 years ago and Chris Lamb committed 4 years ago

Previously the temporary directories where all left in place until the
end of the process, when a massive cleanup was being run. The cause
was the _DIRS variable that was holding references to the
TemporaryDirectory objects, so their destructor was not running.

We now remove the _DIRS list completely (replacing it with _BASEDIR for
storing only the parent temporary directory). As a result, the temporary
directories and their contents are being cleaned up automatically when
the class destructor runs.

This in turn requires modifications to preexisting code:

1. Code that was directly using `get_temporary_directory().name`
   stopped working; the object from `get_temporary_directory()`
   needs to be referenced directly to keep it alive.
2. `get_temporary_directory()` is now starting a `with` block
   (context manager) where it was straightforward.