Finish the improvements I planned.

- No more manual args manipulation -- getopts used for everything.
  As a result, options can be in any position, now, even before the
  subcommand.
- The additional options for test, bench, and dist now appear in the
  help output.
- No more single-letter variable bindings used internally for large
  scopes.
- Don't output the time measurement when just invoking 'x.py'
- Logic is now much more linear.  We build strings up, and then print
  them.

src/bootstrap/bootstrap.py

@@ -591,9 +591,10 @@ def bootstrap():
 
 def main():
     start_time = time()
+    help_triggered = ('-h' in sys.argv) or ('--help' in sys.argv) or (len(sys.argv) == 1)
     try:
         bootstrap()
-        if ('-h' not in sys.argv) and ('--help' not in sys.argv):
+        if not help_triggered:
             print("Build completed successfully in %s" % format_build_time(time() - start_time))
     except (SystemExit, KeyboardInterrupt) as e:
         if hasattr(e, 'code') and isinstance(e.code, int):
@@ -601,7 +602,7 @@ def main():
         else:
             exit_code = 1
             print(e)
-        if ('-h' not in sys.argv) and ('--help' not in sys.argv):
+        if not help_triggered:
             print("Build completed unsuccessfully in %s" % format_build_time(time() - start_time))
         sys.exit(exit_code)