Added some compiler statistics utilities. The idea is that all you do

Added some compiler statistics utilities.  The idea is that all you do
is place a call to SAMPLE/1 or SAMPLE/2 at the appropriate place in
the code, and NOT rely on their arguments for a side effect.

Each statistic has a name (a symbol), a type (a symbol) and perhaps
some optional parameters.  The calls to SAMPLE/n create the statistic
if it unknown, and then incorporate the data for generating a report.

  (COMPILER:RESET-STATISTICS!)
  (COMPILER:DISPLAY-STATISTICS)
  (SAMPLE/1 '(name type [parameters]) datum)
  (SAMPLE/2 '(name type [parameters]) datum1 datum2)

Current unary statistics are

  '(name AVERAGE) <x>)		- number, sum and average
  '(name HISTOGRAM VECTOR)	- histogram small non-negative integers
  '(name HISTOGRAM HASH-TABLE)	- histogram numbers, strings, symbols etc
  '(name HISTOGRAM)		- same as HASH-TABLE

Currently there are no binary statistics.