pgsql: Fix assorted bogosities in cash_in() and cash_out().

Fix assorted bogosities in cash_in() and cash_out().

cash_out failed to handle multiple-byte thousands separators, as per bug
#6277 from Alexander Law. In addition, cash_in didn't handle that either,
nor could it handle multiple-byte positive_sign. Both routines failed to
support multiple-byte mon_decimal_point, which I did not think was worth
changing, but at least now they check for the possibility and fall back to
using '.' rather than emitting invalid output. Also, make cash_in handle
trailing negative signs, which formerly it would reject. Since cash_out
generates trailing negative signs whenever the locale tells it to, this
last omission represents a fail-to-reload-dumped-data bug. IMO that
justifies patching this all the way back.

Branch
------
REL8_3_STABLE

Details
-------
http://git.postgresql.org/pg/commitdiff/b52ca458e9763442a0ece483c0529d50344557aa

Modified Files
--------------
src/backend/utils/adt/cash.c | 205 ++++++++++++++++++++++--------------------
1 files changed, 109 insertions(+), 96 deletions(-)