Given an RF input file, this runs it through the complete decoding
toolchain, and does optional sanity checks on the results.

It's careful to run all the tools from the source directory, so you
don't need to install anything first.

On pushes and pull requests, this builds all of ld-decode, and runs
test-decode on CAV/CLV PAL/NTSC samples from ld-decode-testdata.
The sanity check parameters are based on the results as of the rev6
release (with bPSNR backed off by 0.5 dB to allow for some variation).

Add regression tests using GitHub CI

…ame place

Remove the executables that don't exist any more, and add the testout
directory that test-decode creates.

filtermaker is now in scripts, and deemp.h is now part of the filter
library.

The modules are now all in an "lddecode" package. The scripts that are
useful for end-users will be installed.

I've done this with distutils.core rather than setuptools because it
doesn't need any of the extra stuff setuptools provides, and
distutils.core is usefully less picky about where it installs to.

I've also trimmed some imports that aren't being used.

Update the .gitignore files.

Make ld-decode into a Python package

There's no standard for this in qmake, but PREFIX seems to be a common
name in other projects.

This tries to cover building and installation for typical users, and
supports GNU-style prefix and DESTDIR variables for installing in custom
prefixes and package staging dirs.

Variables are provided to override qmake and python3 because some
systems have different names for these (qmake-5, python3.7, ...).

Make the top-level Makefile build/install all of ld-decode

…tors

…nd random tweaks

…nput

…nformation messages

…able sources

These are QByteArrays, so using the fill method won't do the right thing
when we're trying to fill with a 16-bit value.

SourceField::loadFields used to load field 1 then fill it with black
when it needed a dummy black field. This doesn't work when input is from
a pipe (because it would need to seek), so just resize the field data to
the right size instead.

Fix piped TBC input with 3D chroma decoders