Implemented and tested some trees.

The trees are refactored and templated versions. Included trees:
- binary search tree.
- red-black tree.
- left-leaning red-black tree.

Updated test.cpp to include basic testing of the trees.

Needs further refactoring so names, scope and the like make more sense.
Merge branch 'master' of https://github.com/dlebech/data-structures-cpp

Conflicts:
	README.md