Defines format of string binary serialization

Values of this enumeration:

• VariableLength_Raw
• VariableLength_NullTerminated
• VariableLength_8BitPrefix
• VariableLength_16BitLEPrefix
• VariableLength_32BitLEPrefix
• VariableLength_16BitBEPrefix
• VariableLength_32BitBEPrefix
• VariableLength_LEB128Prefix
• FixedLength_Raw
• FixedLength_NullTerminated