Adicionado busca em profundidade e método para montar o caminho a partir da árvore de caminhos mais curtos
Added the first tests and cleaned the dfs code.
Added breadth-first search and some tests
Added tests to the build_path
Now the graph supports distance between vertices.
Added uniform cost graph search.
Now bfs and dfs return the path, not the heap-paths.
Merge remote branch 'origin/master'