Don't close analyzer in LuceneLoggerBackend.close

It' not neccesary to close an analyzer
Add protocol specification
LuceneLoggerBackend.log throws a more descriptive exception if
msg.size() == 0
Replace parseKeyValue(String) with getValue(String, String) in
LuceneLoggerBackend
Implement message parsing in LuceneLoggerBackend.logNick
Add @author and @version to LuceneLogger
Adjust indentations in LuceneLoggerBackend
Remove try-catch block in LuceneLoggerBackend.initialize
Add KeyValueMap for LuceneLoggerBackend