bug fmt_double

Hi,

fmt_double has problems when formating double values like "[-]0.*".
example:

#include <buffer.h>
#include <fmt.h>
#include <stdio.h>

void print_double(double d);

int main() {
   print_double(-0.610309);
   print_double(1.0);
   print_double(-0.6);
   print_double(-6.123);
   print_double(0.6);
   return 0;
}

void print_double(double d) {
   printf("%f\n", d);
   char dbuf[30];
   size_t dlen = 0;
   dlen = fmt_double(dbuf, d, 30, 10);
   buffer_put(buffer_1, dbuf, dlen);
   buffer_puts(buffer_1, "\n");
   buffer_flush(buffer_1);
}

# output:
-0.610309
-6103089999
1.000000
1.000000000
-0.600000
-5999999999
-6.123000
-6.123000000
0.600000
5999999999

for [-]0.* the decimal point is missing

gcc  4.3.2
libowfat 0.27 / cvs from 22.00 CET