split experimental features from stable

...go_experimental/test-src/graph/spanningtree/KruskalTest.h

alib2algo_experimental/test-src/graph/traverse/BfsTest.cpp

alib2algo_experimental/test-src/graph/traverse/BfsTest.h

alib2algo_experimental/test-src/graph/traverse/DfsTest.cpp

alib2algo_experimental/test-src/graph/traverse/DfsTest.h

alib2algo_experimental/test-src/main.cpp

...gology/exact/BackwardNondeterministicDAWGMatchingTest.cpp

...ingology/exact/BackwardNondeterministicDAWGMatchingTest.h

.../test-src/stringology/exact/FactorOracleAutomatonTest.cpp

...al/test-src/stringology/exact/FactorOracleAutomatonTest.h

...mental/test-src/stringology/exact/SuffixAutomatonTest.cpp

...rimental/test-src/stringology/exact/SuffixAutomatonTest.h

alib2data/src/string/StringFeatures.h

alib2data_experimental/Doxyfile

alib2data_experimental/makefile

alib2data_experimental/makefile.conf

alib2data_experimental/src/graph/Graph.cpp

alib2data_experimental/src/graph/Graph.h

alib2data_experimental/src/graph/GraphBase.h

alib2data_experimental/src/graph/GraphClasses.h