Replaces the custom one which was erroneously added during development.
Fixes #746.

_sandboxremote.py: Use the standard SandboxError

Closes #746

See merge request !931

Update our instructions/examples regarding how we declare remote caches

See merge request !932

There are arguments for and against using onerror - see issue #735
for details.

Use _force_rmtree instead of custom code.

Closes #735

See merge request !927

This will now return paths in the same order as list_relative_paths.