package.js otimization

I removed some unnecessary code:

```
where = where || ["client", "server"];
where = where instanceof Array ? where : [where];
```
You don't need this I guess.

```
if (where === "client" || (where instanceof Array && where.indexOf("client") !== -1))
```

You don't have to check if its client, meteor filter the `.use` and `.add_files` to the `where` passed as 2nd argument.

PS: Sorry about possible english mistakes.