tidy: don't use protected fields, repeat access modifiers

alib2graph_data/src/edge/Edge.hpp

alib2graph_data/src/edge/EdgeBase.hpp

alib2graph_data/src/edge/capacity/CapacityEdge.hpp

alib2graph_data/src/edge/weighted/WeightedEdge.hpp

alib2graph_data/src/graph/GraphBase.hpp

alib2graph_data/src/graph/directed/DirectedGraph.hpp

alib2graph_data/src/graph/directed/DirectedMultiGraph.hpp

alib2graph_data/src/graph/mixed/MixedGraph.hpp

alib2graph_data/src/graph/mixed/MixedMultiGraph.hpp

alib2graph_data/src/graph/undirected/UndirectedGraph.hpp

...2graph_data/src/graph/undirected/UndirectedMultiGraph.hpp

alib2graph_data/src/grid/GridBase.hpp

alib2graph_data/src/grid/square/SquareGrid.hpp

alib2graph_data/src/grid/square/SquareGrid4.hpp

alib2graph_data/src/grid/square/SquareGrid8.hpp

alib2graph_data/src/grid/square/WeightedSquareGrid4.hpp

alib2graph_data/src/grid/square/WeightedSquareGrid8.hpp

alib2graph_data/src/node/Node.hpp