converts a js object into a ddb object
function toDDB(data, mergeInto) {
	var result = mergeInto || {}
	var keys = Object.keys(data)

	for (var i = 0; i < keys.length; i++) {
		var p = keys[i]
			
		result[p] = toDDBValue(data[p])
	}

	return result
}