Allow multiple calls to order in aggregates

[Locke]

In Model.find() you can order by multiple columns, this was not possible in aggregates

[Locke]

I just noticed ChainFind.order() checks if the property starts with "-" and applies descending order but AggregateFunctions.order() doesn't.

It's also not possible to pass an order at the initialization of an aggregation, but on find() it is.

Are these points blocking the merge?

[dresende]

We're having some nasty thing I don't know yet that is making the tests fail. I want to fix it before accepting this. About the order, there's an utility in Utilities.js created recently that we have to change everything in the lib that uses order to pass it through this utility.

[dresende]

I found the bug, it was sqlite3 v2.1.10. I had to downgrade to v2.1.7.

Although this pull now passes, I'm going to refuse it and change the .order() to accept any number of arguments and use Utilities.standardizeOrder. Thank you pointing this out.