Use 16 bytes secure random instead of a number from 0 to 999.  This
increases entropy in the salt from about 10 bits to 128 bits.

Reported by:	Pierre Carrier <pierre carrier#airbnb com>
Security:	CVE-2014-0083
Merge pull request #79 from delphij/master

Use 16 bytes secure random instead of a number from 0 to 999.  This