add support for systemd >= 209 library names
imudp cleanup: remove no longer needed calling parameter
omfwd: add new "udp.senddelay" parameter
testbench: add a send-delay to UDP test

It turned out that on some systems we had UPD message loss. This
was not due to an rsyslog problem, but rather due to UDP policies
which permit dropping packages if buffers are overrun. It actually
happened and doing a slight delay solves the situation.
fix for missing include-path for liblogging dependency in test
Fix missing headers that clang complains about