new configuration structure:
peer_cfg: configuration related to a peer (authenitcation, ...=
ike_cfg: config to use for IKE setup (proposals)
child_Cfg: config for CHILD_SA (proposals, traffic selectors)
a peer_cfg has one ike_cfg and multiple child_cfg's
stroke now uses fixed count of threads
splitted authenticator to have a separate implementation for each auth_method_t
using va_copy to clone va_lists, should fix proplems on AMD64
some other cleanups