counters + return of log summary, explain log

• Counters are very dense and still difficult to parse. Need a way to organise / categorise / present them so the user doesn't ignore them by default. (see Counter groups below)
• Think about moving counters below output viewer or below log viewer
• ??? profit

TODO: counter "groups"

• Unpacker counters (alg name starts with Unpack or counter name contains bank )
• Standard Particle algorithms
• User-configured selections and tupling algorithms (how do we pick these out)
  • Use DecayTreeTuple specific log messages matching algorithm name
• Application specific counters (Algorithm names are always the same)
• Other/uncategorised