Support for reading 2.1 log files and upgrading from 2.1 store files

What do you think about adding one more method ```byteCode()``` that will return constants from ```LogEntryByteCodes```? With such change it would be possible to create a single generic ```LogEntryParserDispatcher<T extends Enum<T> & LogEntryParser>``` that iterates over enum elements and picks the needed parser.