Get valid data

[iamludal]

Feature request

Currently, $gump->run($data) returns $data, which is redundant, and would return unwanted keys.

As this might be useful though in some cases that I don't know about, I suggest a new method to only get valid data.

Example

$gump->validation_rules(['title' => 'required']);
$gump->run(['title' => 'Sample title', 'content' => 'Sample content']);
$validData = $gump->validData(); // ['title' => 'Sample title']