exit 1 if configuration file is invalid
usefull in reload/restart init script, when file is invalid, die with
errors.
Merge pull request #58 from Cofyc/checkconf

exit 1 if configuration file is invalid
make nc_test_conf return bool
Merge remote-tracking branch 'upstream/master' into kqueue_pull
Ensure that we don't evbase_destroy(NULL). Give evbase_destroy() the same semantics as free() - that is, passing a NULL pointer in is just a no-op.
Give nc_epoll.c:evbase_destroy() the same semantics as free() in that passing NULL in is a no-op.