Add a better Single File Application example

[tacman]

The original example didn't work because it was expecting a return value. This example is a bit more real-world.

[tacman]

I also add a filename and instructions for running it. I don't understand the second part of the page, where the command can be registered. Is that for bin/console? Or if you want to have your own set of commands, like bin/my-files, where you would have file-counter and others, like bin/console has?

[alexislefebvre]

This PR contains too many commits. You should be able to rebase it on 7.1 and remove the unwanted commits, or it may be simpler to create a new branch from 7.1 and cherry-pick the commits you want. If you can't reduce the commits for this PR, close it and open a new PR which should contain a few commits only.

[OskarStark]

I switched back to 7.2 target branch, we can adjust while merging, but shouldn't we target 6.4?

[OskarStark]

Suggested change

	Now run it with
	php bin/file-counter.php
	php bin/file-counter.php --all
	Now run it with:
	.. code-block:: bash
	php bin/file-counter.php
	or
	.. code-block:: bash
	php bin/file-counter.php --all

[OskarStark]

Please use a use statement

[OskarStark]

Suggested change

	;
	$count = iterator_count($finder);
	$output->writeln( "$dir has $count " .
	($all ? "files" : "files in source control"));
	return SingleCommandApplication::SUCCESS;
	;
	$count = iterator_count($finder);
	$output->writeln("$dir has $count " . ($all ? "files" : "files in source control"));
	return SingleCommandApplication::SUCCESS;

[OskarStark]

Suggested change

	<?php // bin/file-counter.php
	require __DIR__.'/../vendor/autoload.php';
	// bin/file-counter.php
	<?php
	require __DIR__.'/../vendor/autoload.php';