Performance tests from Martin Ankerl

[dumblob]

How does this hashmap perform with regards to the thorough testing @martinus did in his blog series about the current cutting edge hash maps?

[martinus]

I've tried to add it when creating the benchmark, but unfortunately the map doesn't have a default constructor so I've stopped right there. See https://github.com/martinus/map_benchmark#maps-i-couldnt-add

[rigtorp]

Yes I think the empty key should be selected through a template parameter instead of a constructor argument at runtime.