[core:resources] filename text selects with out extention on file copy
[VolumeDriver] new func `getArchivers` for calls from `_checkArchivers`

Added new function `getArchivers()` for calls from `_checkArchivers()`.

`getArchivers()` catching exists archivers into session data for improve
performance.

ex.
```php
protected function _checkArchivers() {
	$this->archivers = $this->getArchivers();
	return;
}
```

And, added cmd check about `7z` for windows server.

ref. #550, #722
Merge branch '2.x' into 2.1