use static composers and parsers in fact. classes

alib2/src/ExceptionFromXMLParser.cpp

alib2/src/ExceptionFromXMLParser.h

alib2/src/ExceptionToXMLComposer.cpp

alib2/src/ExceptionToXMLComposer.h

alib2/src/FromXMLParsers.cpp

alib2/src/FromXMLParsers.h

alib2/src/ToXMLComposers.cpp

alib2/src/ToXMLComposers.h

alib2/src/alphabet/SymbolFromXMLParser.cpp

alib2/src/factory/LabelFactory.cpp

alib2/src/factory/LabelFactory.h

alib2/src/factory/RegExpFactory.cpp

alib2/src/factory/RegExpFactory.h

alib2/src/factory/StringFactory.cpp

alib2/src/factory/StringFactory.h

alib2/src/factory/SymbolFactory.cpp

alib2/src/factory/SymbolFactory.h