[2.1][File Upload] RenameUpload filter rewrite w/option to use uploaded 'name'

Rewrite of the `Zend\Filter\File\RenameUpload` filter to be easier to use, and with an additional feature to use the `$_FILES['name']` as the target filename.

Also, some misc docs cleanup and a cornercase fix of `Zend\Filter\File\Rename` (from my earlier $_FILES-support-in-filters changes).

RenameUpload usage example:

```php
use Zend\Http\PhpEnvironment\Request;

$request = new Request();
$files   = $request->getFiles();
// i.e. $files['my-upload']['name'] === 'myfile.txt'

$filter = \Zend\Filter\File\RenameUpload("./data/uploads/");
$filter->setUseUploadName(true); // Use the original upload filename
echo $filter->filter($files['my-upload']);
// File has been moved to "./data/uploads/myfile.txt"
```

Docs: https://raw.github.com/cgmartin/zf2-documentation/f32980cd35bdea21b6560d5dee4d878af002313f/docs/languages/en/modules/zend.filter.file.rename-upload.rst