Added unit tests for the graph labeling stuff.

dlib/test/CMakeLists.txt

@@ -46,6 +46,7 @@ set (tests
    geometry.cpp
    graph.cpp
    graph_cuts.cpp
+   graph_labeler.cpp
    hash.cpp
    hash_map.cpp
    hash_set.cpp

dlib/test/makefile

@@ -61,6 +61,7 @@ SRC += find_max_factor_graph_viterbi.cpp
 SRC += geometry.cpp
 SRC += graph.cpp
 SRC += graph_cuts.cpp
+SRC += graph_labeler.cpp
 SRC += hash.cpp
 SRC += hash_map.cpp
 SRC += hash_set.cpp