cleaned up HashValueJoin and added test
added namespace to perf_regression/HashValueJoin.cpp
minor fix to make merge easier
Merge branch 'feature/cleanup_HashValueJoin' of https://github.com/timbokopter/hyrise into timbokopter-feature/cleanup_HashValueJoin

Conflicts:
	src/lib/access/HashValueJoin.hpp
Merge pull request #186 from bastih/timbokopter-feature/cleanup_HashValueJoin

HashValueJoin pr refresh