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;
Matching algorithms' common interface refactoring;
Moving builders into `generate` package;
Introducing weighted-graph-generator adapter; replacing redundant `GraphBuilder` interface with `GraphGenerator` one
Merge pull request #27 from alexeykudinkin/kuhn-munkres

Kuhn-Munkres (Hungarian) algorithm added