Added Kuhn-Munkres (Hungarian) algorithm for finding perfect matching having minimal weight in bipartite graphs;
Abstracted Matching/WeightedMatching interfaces;
Adapted Edmond's 'Blossom Shrinking' and Hopcroft-Karp algorithm to accommodate interfaces derived;
Added tests for KM algorithm;
Added graph-builder interface to accommodate facilities for building graphs upon matrix representation;
 Added matrix-graph-builders for simple-weighted graphs instances;