trafgen: Fix typo in message

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
trafgen: Move common duplicate calls from xmit_*_or_die to main_loop

Also call xmit_precheck before accessing ctx (when calling
compile_packets).

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Merge branch 'trafgen' of git://github.com/tklauser/netsniff-ng
docs: add Tobias into Authors

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
trafgen: move precheck after packets are compiled

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>