Buffer overrun in printable_binnary

[guillerodriguez]

There is a buffer overrun in the printable_binnary function in pkutils.c. It can be triggered with the following test case:

char data[48];
int i;
data[0] = 'a';
for (i = 1; i < 48; i++)
  data[i] = -1;

pk_log_raw_data(PK_LOG_ALL, "app", data, 48);

This is probably the issue that causes #29.