Function _cfgOption
Convenience method to get the value of the array config variable by its key
		
		Package: PHPLucidFrame\Core
Copyright: Copyright (c), PHPLucidFrame.
License: MIT License This source file is subject to the MIT license that is bundled with this source code in the file LICENSE
Located at lc.php
	
	Copyright: Copyright (c), PHPLucidFrame.
License: MIT License This source file is subject to the MIT license that is bundled with this source code in the file LICENSE
Located at lc.php
string | 
		$name | 
		The config array variable name without prefix | 
string | 
		$key | 
		The key of the config array of which value to be retrieved | 
			mixed|string|null
		 | 
		The value of a single column of the config array variable |