Version 0.43 released. Shared-IPs, random VC credentials

version 0.43 delivers:
- shared IPs facility, which allows using of
a limited pool of client IP-addresses by
any number of virtual clients;
- random clients feature, which allows using
e.g. 100 clients to simulate a load of e.g.
1000000 clients by choosing client credentials
randomly;
- compilation, FTP, IPv6 bugfixes;