throw exception on unregistration of non-existent entry

alib2abstraction/src/registry/CastRegistry.hpp

alib2abstraction/src/registry/ContainerRegistry.hpp

alib2abstraction/src/registry/ImmediateRegistry.hpp

alib2abstraction/src/registry/NormalizeRegistry.hpp

alib2abstraction/src/registry/ValuePrinterRegistry.hpp

alib2raw/src/registry/RawReaderRegistry.hpp

alib2raw/src/registry/RawWriterRegistry.hpp

alib2str/src/core/stringApi.hpp

alib2str/src/registration/StringRegistration.hpp

alib2str/src/registry/StringReaderRegistry.hpp

alib2str/src/registry/StringWriterRegistry.hpp

alib2xml/src/core/xmlApi.hpp

alib2xml/src/registry/XmlComposerRegistry.hpp

alib2xml/src/registry/XmlContainerParserRegistry.hpp

alib2xml/src/registry/XmlParserRegistry.hpp