Removed useless code to count the number of calls into the profiler.

Added support for saving the names of the functions observed into the
profile log.
Added support for using the profiler to measure coverage without collecting
timing information (which is the slow part).  Coverage logs can also be
substantially smaller than profiling logs where per-line information is
being collected.
Updated comments on the log format; corrected record type values in some
of the record descriptions.