Event extractor

# Introduced event extractor for packets
instead of having two data convert plugins the old data converter plugin is extended by two new functions.     
- a function which shows how many events  Read out frames are in the packet
- a function to extract a certain ROF from the packet

# sync algorithm 
the sync algorithm now can also handle cases in which there is no tlu or in which no synchronization is needed 

# file reader 
both file readers are now derived from one base class file reader.
this makes it easier to use eudet type of files and aida type of files.