Use TPIE allocation inside of 'std::shared_pointer'

[SSoelvsten]

Currently, all structs and files constructed with Adiar are not counted as part of the memory usage inside of TPIE. That is not a big problem, as they take up so little space, but we should attempt to be better at counting the real memory usage of ours.

We may want to look into whether we can use tpie_new and tpie_delete. In TPIE they already provide a wrapper for the unique pointer with make_unique where the tpie_delete is already automatically added with tpie_deleter. We should be able to repeat the same for a shared pointer.

In fact, if we can get it to work, then we might as well create a Pull Request to TPIE too.

[SSoelvsten]

Other BDD packages like Sylvan only counts the memory usage of the unique node table and the memoisation tables; yet, LACE also takes up space and it has a few other things too. That is, our current way of accounting for memory is akin to Sylvan's.