[Console] added ProgressBar (to replace the stateful ProgressHelper class)

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | yes
| Tests pass?   | yes
| Fixed tickets | #9951, related to #9788
| License       | MIT
| Doc PR        | n/a

TODO:

 - [ ] submit a PR on the docs

This PR deprecated `ProgressHelper` in favor of `ProgressBar`. The main difference is that the new `ProgressBar` class is stateless, which allows for more than one bar to be displayed at a time:

```php
use Symfony\Component\Console\Helper\ProgressBar;
use Symfony\Component\Console\Output\ConsoleOutput;

$output = new ConsoleOutput();

$bar1 = new ProgressBar($output, 10);
$bar2 = new ProgressBar($output, 20);
$bar2->setProgressCharacter('#');
$bar1->start();
print "\n";
$bar2->start();

for ($i = 1; $i <= 20; $i++) {
    // up one line
    $output->write("\033[1A");
    usleep(100000);
    if ($i <= 10) {
        $bar1->advance();
    }
    print "\n";
    $bar2->advance();
}
```

And here is how it looks like when run:

![progress-bars](https://f.cloud.github.com/assets/47313/2300612/4465889a-a0fd-11e3-8bc2-b1d2a0f5dc3d.gif)