Start working on new haccable
Refactor Haccs again.  Just plain pointers this time.
New haccable works!  Yay!
Implement attrs and elems in haccables
Test haccable a little more
Add in haccable_standard and haccable_integration
Standard Haccability for std::vector (hacc::Array)
Put wrappers around get_id and find_by_id.
Far better GetSet handling.  Also change from_hacc to value_from_hacc and such.
Add PolyP and base declarations in HCB.
Test (and fix) haccable variants.
Make HaccTable::by_cpptype autofivify, thus solving the initialization order problem.
Add to_hacc via follow_pointer.
Implement (untested) update_from_hacc via canonical_pointer
Wrangle out some bugs in canonical_pointer
Start adding pointers and ids and refs and stuff to haccable
Make pointer changes work with old tests.
First crack at implementing real address<->id conversion.
Whoowie!  Internal pointers, at least trivial self-referential ones, work!  There are a couple bugs left though.
Automatically instantiate more classes.

That we do this in the getset code is a bit annoying.