function fnInvertKeyValues( aIn )
{
	var aRet=[];
	for ( var i=0, iLen=aIn.length ; i<iLen ; i++ )
	{
		aRet[ aIn[i] ] = i;
	}
	return aRet;
}
Switch the key value pairing of an index array to be value key (i.e. the old value is now the
key). For example consider [ 2, 0, 1 ] this would be returned as [ 1, 2, 0 ].
 @method  fnInvertKeyValues
 @param   array aIn Array to switch around
 @returns array