decouple tree xmlApi from tree data structures

alib2algo/src/tree/generate/RandomTreeFactory.cpp

alib2data/src/tree/TreeBase.h

alib2data/src/tree/ranked/PostfixRankedTree.cpp

alib2data/src/tree/ranked/PostfixRankedTree.h

...2data/src/tree/ranked/PrefixRankedBarNonlinearPattern.cpp

alib2data/src/tree/ranked/PrefixRankedBarNonlinearPattern.h

alib2data/src/tree/ranked/PrefixRankedBarPattern.cpp

alib2data/src/tree/ranked/PrefixRankedBarPattern.h

alib2data/src/tree/ranked/PrefixRankedBarTree.cpp

alib2data/src/tree/ranked/PrefixRankedBarTree.h

alib2data/src/tree/ranked/PrefixRankedNonlinearPattern.cpp

alib2data/src/tree/ranked/PrefixRankedNonlinearPattern.h

alib2data/src/tree/ranked/PrefixRankedPattern.cpp

alib2data/src/tree/ranked/PrefixRankedPattern.h

alib2data/src/tree/ranked/PrefixRankedTree.cpp

alib2data/src/tree/ranked/PrefixRankedTree.h

alib2data/src/tree/ranked/RankedNonlinearPattern.cpp

alib2data/src/tree/ranked/RankedNonlinearPattern.h

alib2data/src/tree/ranked/RankedPattern.cpp

alib2data/src/tree/ranked/RankedPattern.h