Merge one second patch

This patch reverses the changes made by commits f7ac43f71f22 and
5954968dd8ee. In these, the tinydns(8) server was made to read its
data file ones during initialisation and later when signalled via
SIGUSR1.

Though it improved performance, it proved to be problematic for
some users who could not signal(SIGUSR1) to a server that its data
file has changed and needs to be reloaded into memory.

Now with the one-second-path, server would reload its data file at
every one second. Thus leaving no need for any signal or restarting
the service.

Thanks to Mr Lennert Buytenhek for creating this patch and for making
it available for all.
    -> http://tinydns.org/one-second.patch