Add embedded/recursive object capability to MyArchive structure

[dgets]

In order to preserve our tree structure for embedded archive re-rolling, we're going to need MyArchive to be able to hold links to other MyArchive objects. An array of these object references within the data structure will, at this point, most likely suffice. It may turn out more efficient, or maintainable, to consolidate some of the archive entry data, if these end up becoming more complex.

This issue is a part of #8.