Refactor the statistics reporting for the concolic mode.

Removed a bunch of hacks where we would double count statistics and then remove the etra counts in the trace merger.

Also added reporting of the success/failure of traces, and how many unsat/unsolved/missed nodes were seen.

Finally added reporting of how much symbolic information was seen during the event sequence part of the tree.
Merge branch 'master' of github.com:cs-au-dk/Artemis