public static function array_merge_deep(array $array1, array $array2)
	{
		$merged = $array1;

		foreach ($array2 as $key => $value) {
			if (is_array($value) && isset($merged[$key]) && is_array($merged[$key])) {
				$merged[$key] = self::array_merge_deep($merged[$key], $value);
			} elseif (is_numeric($key)) {
				// Numeric key. Look at values instead of keys to determine if it already exists.
				if (!in_array($value, $merged)) {
					$merged[] = $value;
				}
			} else {
				$merged[$key] = $value;
			}

		}

		return $merged;
	}