changes to Crypt_Random

The diff, in this case, is kinda misleading. Here's that part of Random.php before the https://github.com/terrafrost/phpseclib/commit/2ba1f32ee1490a80bbeec97013348dcdcc1af3e9 commit, with the comments removed:

```php
        if (is_string($crypto)) {
                $i = pack('H*', sha1(microtime()));
                $r = pack('H*', sha1($i ^ $v));
                $v = pack('H*', sha1($r ^ $i));
                $result.= $r;
            }
            return substr($result, 0, $length);
        }
```

[Link](https://github.com/terrafrost/phpseclib/blob/e6f87318f522132178839bd90fd21762cba869c9/phpseclib/Crypt/Random.php)

Here it is after:

```php
        if (is_object($crypto)) {
            $result = '';
            while (strlen($result) < $length) {
                $i = $crypto->encrypt(microtime()); // strlen(microtime()) == 21
                $r = $crypto->encrypt($i ^ $v); // strlen($v) == 20
                $v = $crypto->encrypt($r ^ $i); // strlen($r) == 20
                $result.= $r;
            }
            return substr($result, 0, $length);
        }
```
[Link](https://github.com/terrafrost/phpseclib/blob/2ba1f32ee1490a80bbeec97013348dcdcc1af3e9/phpseclib/Crypt/Random.php)