This is in preparation for adding --ecm-only and -ecm-and-emm-only
options.

Refactor host and port parsing code into a function. It'll be used
when setting up input, output and camd server.

This patch adds two new EMM counters in the regular stats messages.

Now the counters are:

 Received  - How much EMMs were received from the input.
 Skipped   - How much EMMs were skipped because of filtering.
 Sent      - How much EMMs were added to the sending queue.
 Processed - How much EMMs were sent to the CAMD server for processing.

This patch adds support for connecting to CAMD over IPv6. Nice addition
is that now tsdecrypt tries each of the addresses returned when CAMD
hostname is resolved and connects to the one that works. Resolving
of the server address is done before each connect, which allows for
uninterupted migration of CAMD servers by just changing their DNS
record.

IPv6 functionality can be disabled by using -4/--ipv4 options or
if you fancy only IPv6 servers -6/--ipv6 can be used.

It is anti-social to just say that there is an error, when we
have a nice way of saying what the error is.

The limitation is that resolving the hostname is performed only
once at tsdecrypt startup. If DNS changes while tsdecrypt is running,
tsdecrypt won't notice that.

The option correct option is --no-output-filter.

By using this option output can be disabled if there is no currently
received code word.

Use "make ffdecsa" to build tsdecrypt with ffdecsa support
or "make dvbcsa" to build with libdvbcsa (this is still the default).

no-output-filter better describes what the parameter does.
Also fix man page description. output-filter still works but
it is undocumented and kept only for backwards compatability.