Removed all @category, @package, and @subpackage annotations

- Per #2743, and following on #2953 and discussion on the ML
- Also removes empty docblocks, and empty lines at the end of docblocks
- Library only; phpdoc is never run on tests anyways, and did not want to
  potentially create breakage due to test expectations that relied on
  annotations. At this time, all tests pass.

PR created using two tools:

- `sed -ri '/^ \* \@(subpackage|package|category)/d' Zend/**/*.php`
- `for f in Zend/**/*.php;do php clean_empty_docblocks.php $f ; done`

In the latter command, I used the following script:

```php
<?php
$file = $argv[1];

if (!file_exists($file)) {
    echo "Could not open $file\n";
    exit(1);
}

$contents = file_get_contents($file);

// empty docblocks
$contents = preg_replace('#\n\/\*\*[ ]*\n \*\/#', '', $contents);
// trailing empty docblocks
$contents = preg_replace('#\n \*[ ]*(\n \*\/)#', '$1', $contents);
file_put_contents($file, $contents);
exit(0);
```