1.7.x -> 1.8

Completly rewritten Gen-b window, user can now select different options while sending per checkbuttons. Optionaly user can specify which checksums should be updated (ipv4, tcp, udp, icmp).

Also the Gtk calls where now removed from the sending thread, what caused a lot of problems with stability on certain Linux distirbutions before. I hope now the whole program will be much more stable. 


