Release Destructible version 7.0.0-alpha.38.
Release Destructible version 7.0.0-alpha.38.

 * Tidy Docco.
 * Remove `_children` list, tidy Docco.
 * Spread panic to deferrable objects.
 * Fix unit test count.
 * Always propagate destruct when errored.

Closes #254.

bigeasy/destructible