[SR-Dev] first kamailio module ran on the sip-router core

siputils is the first kamailio module that did succesfully run on sip-core.

I did only 2 small changes: - added DEFS+=-DKAMAILIO_MOD_INTERFACE to the Makefile - s/MIN/MIN_int

There are a few modules that would need a little bit more changes, like everything using core send functions (they changed a bit in ser), do_action() and build_*, but in all this cases these are minor updates.

More will be compileable as soon as we unify the fixups, but I think the biggest problem right now is the DB interface (from a module point of view, we still haven't unified the config file).

Andrei