Changes

More build cleanup

* Add new --wwiv_testdata flag to core_tests (or any) so we can use real
  files within the tests.  This will make it easier to add tests for
  parsing real existing files and packets.
* Copy the cl32.dll file as a post-build step so it's consistently
  happening.

Move test fixtures into core/test

* Also add sample testdata for sdk/fido
* add a helper for running the main method of a wwiv googletest
* Use it in core and wwivd

make it easier to use testdata

Added SleepFor to the Clock class

This allows fakeclocks to sleep by advancing the clock without actually
sleeping.

more work on FidoPacket class and tests

get networkf building again, plus find cereal with cmake the right way

More cleanup of NetworkF.

* Add password helper
* Consolidate creating FtnDirectories once when instantiating the class

Add tests for  FindRouteToAddress

Start preparing for C++20

Don't use u8string anywhere since it's a shipwreck
See
https://yehezkelshb.github.io/cpp_proposals/sg20/P1747-dont-use-char8_t-yet-in-P1389.html

Use size_int vs. ssize when we want an int.  Will eventually move to
std::ssize once we upgrade to C++20

Remove EMPTY_FIDO_ADDRESS and use std::optional more.

more work on making networkf testable

Add Config into SdkHelper so it can be more easily used in SDK tests.

Also allow Config to be moved if needed, no harm in allowing that,
although it's not super useful since there's nothing to move, as it just
copies the data.

Use SOCKET and INVALID_SOCKET consistently everywhere.

On Windows SOCKET is an unsigned int, where in the rest of the world
it's an int, this causes signed/unsigned warnings in places when we mix
and match.  Use the defined types consistently and not int, and that
makes the warnings all go away (although there is no semantic change
here)

use new config() method in SdkHelper everywhere

more changes to improve testability

update copyright date to 2022