Fix CMakeList for test

It seems that new versions of CMake overwrite variables in find_package
rather than append.
Revert "Moved operator<< to utils/ostream.hpp header"

This reverts commit f02c1fbe819a78424fcff995f1d17c842058cf89.

Conflicts:
	libvis/include/detail/kdtree_impl.hpp
WIP moving from ported to hsv_aux (tests fail!)
Added serialization for arma::Mat
WIP kdtree serialization