Set version to 0.8.1.

Add tests.

Add Visual Studio 2017 in AppVeyor CI.

Add installation rules in the CMake of the project (Tessil#22)

Update README.md. Fix example.

Add support for large maps/sets (more than 2^32 - 1 elements) through…

… an extra class template parameter (Tessil#18)

Reduce default max load factor to 0.75.

Bug correction, m_load_threshold should never be > max_size().

Update README.md.

Update README.md with more informations.