i18n numeric printing/formating

Dear Mark,

I finally had time to look into the issue and it is mostly about calculating the
groups. E.g. with:

	lang := I18N.LcNumeric language: 'en_US'.
	lang computeNumberOfGroups: 3 => 2
	lang computeNumberOfGroups: 7 => 2

it explains why "123" ends up as ",123" and why "1234567" ends up with
"123,456,.0"

According to the OSX manpage for grouping:

  The sizes of the groups of digits, except for currency values.
  This is a pointer to a vector of integers, each of size char, rep-
  resenting group size from low order digit groups to high order
  (right to left).  The list may be terminated with 0 or CHAR_MAX.
  If the list is terminated with 0, the last group size before the 0
  is repeated to account for all the digits.  If the list is termi-
  nated with CHAR_MAX, no more grouping is performed.


For en_US the grouping is #[3 3] and it looks like the matching
code has issues with exact matches.

holger