Hacked together hybrid map

The Member::Vector class is much more space efficient the Member::MultiMap. But
adding a member at the end destroys the sorting. So this Hybrid class wraps a
Vector and a MultiMap class in a way that entries are added the MultiMap and
then consolidated into the Vector occasionally. Well, the current implementation
is very hacky. Just to see where this goes.
Clean up types in member maps
Add (non-)equality operators to HybridIterator
Sort MultiMap data before dumping.

std::multimap members are only sorted by key, not by value. This sorting isn't
strictly necessary, but makes it easier to compare results for different
map classes.
Cleanup types in Mmap mapping and sort functions
Erase empty map elements when consolidating.