make ranked trees use smart pointers

alib2algo/src/arbology/exact/ExactPatternMatch.cpp

alib2algo/src/arbology/exact/ExactSubtreeMatch.cpp

alib2algo/src/arbology/exact/ExactSubtreeRepeatsNaive.cpp

alib2algo/src/arbology/exact/ExactSubtreeRepeatsNaive.h

alib2algo/src/tree/generate/RandomTreeFactory.cpp

alib2data/src/tree/common/TreeFromXMLParser.cpp

alib2data/src/tree/common/TreeFromXMLParser.h

alib2data/src/tree/ranked/PrefixRankedBarPattern.cpp

alib2data/src/tree/ranked/PrefixRankedBarTree.cpp

alib2data/src/tree/ranked/PrefixRankedPattern.cpp

alib2data/src/tree/ranked/PrefixRankedTree.cpp

alib2data/src/tree/ranked/RankedNode.cpp

alib2data/src/tree/ranked/RankedNode.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

alib2data/src/tree/ranked/RankedTree.cpp

alib2data/src/tree/ranked/RankedTree.h

alib2data/src/tree/unranked/UnrankedNode.cpp