add std::move to all parsers

alib2data/src/alphabet/SymbolFromXMLParser.cpp

alib2data/src/automaton/AutomatonFromXMLParser.cpp

alib2data/src/container/ContainerFromXMLParser.cpp

alib2data/src/container/ContainerFromXMLParser.hpp

alib2data/src/exception/ExceptionFromXMLParser.cpp

alib2data/src/grammar/GrammarFromXMLParser.cpp

alib2data/src/graph/GraphFromXMLParser.cpp

alib2data/src/label/LabelFromXMLParser.cpp

alib2data/src/label/UniqueLabel.cpp

alib2data/src/label/UniqueLabel.h

alib2data/src/primitive/PrimitiveFromXMLParser.cpp

alib2data/src/regexp/RegExpFromXMLParser.cpp

alib2data/src/string/StringFromXMLParser.cpp

alib2data/test-src/grammar/GrammarTest.cpp