DiffieHellman: gracefully handle platforms that fail the sha256 self test, currently only known to be PowerPC. Added support for PHP's built-in hash functions (they were added in 5.1.2) and use them in lieu of the built-in sha256 implementation when available.

/*
 * Auto-completing page/username fields
 * NOTE: A more efficient version of the username field is used for Mozilla browsers. The updated code is in autofill.js.
 */

//
// **** 1.1.5: DEPRECATED ****
// Replaced with jQuery-based mechanism.
//