Fix debug() logging to work with previous changes.
Salvage event-related constants from trace.h.
Move event encoding into event.cc, in prep for changing encoding.
Prepare to add the event type to the event encoding.
Use struct event instead of raw encoded events in the replayer.
Use the new strong types for strevent().
Make event.h the single source of truth about event encodings.
Transform struct event into safer and more convenient Event.
Add IntelHaswell support to init_hpc().
Hardcode Haswell rbc_event encoding, and assert that it matches the IvyBridge encoding.